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NCERT Solutions for Class 9 Science Chapter 4 Structure of The Atom

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NCERT Solutions for Class 9 Science Chapter 4 Structure of The Atom

Edited By Vishal kumar | Updated on Jul 04, 2023 11:29 AM IST

NCERT Solutions for Class 9 Science Chapter 4 – CBSE Free PDF Download

NCERT Solutions for Class 9 Science Chapter 4 Structure of The Atom: After going through the structure of Atom class 9, you must be wondering that; what makes the atom of one element different from another element. Are atoms really indivisible, or are there smaller constituents inside the atom? With the assistance of CBSE NCERT solutions for Class 9 Science Chapter 4 Structure of the Atom, you will find out the answers to these questions. Through the NCERT solutions for the structure of atom chapter, you will also learn about sub-atomic particles and the various models that have been introduced to describe how these particles are arranged within the atom.

NCERT class 9 science chapter 4 question answer contains exercise-wise solutions that are created by the subject experts of Careers360. class 9 Chapter 4 Science, Structure of the Atom includes important topics and theories such as Thomson's model of an atom, Rutherford's model of an atom, Bohr's model of an atom, neutrons, etc. All these theories are very important for the exams. Apart from online solutions, the structure of atom class 9 pdf is also available, which students can download and use offline anytime, free of charge.

Free download class 9 science chapter 4 exercise question answer PDF for CBSE exam.

NCERT Solutions for Class 9 Science Chapter 4 Structure of The Atom

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NCERT Solutions for Class 9 Science Chapter 4 Structure of The Atom Solutions: Solved In-text Questions

Topic 4.1 Charged particles in the matter?

Q. 1. What are canal rays?

Answer:

Canal rays are the positively charged radiations which consist of positively charged particles of atoms. they can pass through the perforated ( pierced ) cathode and then travel towards another cathode in a gas discharge tube.

They were given the name Canal rays by E. Goldstein in 1866 who discovered these radiations.

Q. 2. If an atom contains one electron and one proton, will it carry any charge or not?

Answer:

The proton is a positively charged particle and the electron is a negatively charged particle. their magnitude is equal and hence net charge in an atom is zero.

NCERT free solutions for class 9 science chapter 4 Structure of the Atom

Topic 4.2 The structure of an atom

Q. 1. On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole.

Answer:

According to Thomson’s model of an atom, an atom consists of a sphere of a positive charge.

The positive charge in the atom is spread all over like the red edible part of a watermelon, while the electrons are studded in the positively charged sphere, just like the seeds in the watermelon.

As negative and positive charges are equal in magnitude, they balance each other and thus the atom becomes electrically neutral as a whole.

Q. 2. On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?

Answer:

On the basis of Rutherford’s model of an atom, the subatomic particle which is present in the nucleus of an atom is Proton which is a positively charged particle.

Q. 3. Draw a sketch of Bohr’s model of an atom with three shells.

Answer:

The sketch of Bohr’s model of an atom with three shells:

1651484687087

Q. 4. What do you think would be the observation if the \alpha -particle scattering experiment is carried out using a foil of a metal other than gold?

Answer:

If a foil of a heavy metal like platinum is used, then the observations in the alpha-particle scattering experiment would be the same as that in the gold foil experiment.

If a foil of a light metal like lithium is used, then the observations in the alpha-particle scattering experiment would not be the same because these metal are not so malleable so the thin foil is difficult to obtain.

The problem with not using thin foil is that the number of the alpha particle will bounce back from the thick foil and the location of positive mass would be difficult to find.

CBSE NCERT solutions for class 9 science chapter 4 Structure of the Atom

Topic 2.4.2 Neutron

Q. 1. Name the three sub-atomic particles of an atom.

Answer:

The three sub-atomic particles of an atom are :

1. Electron: a negatively charged particle

2. Proton: a positively charged particle

3. Neutron: a neutral particle

Q. 2. Helium atom has an atomic mass of 4 u and two protons in its nucleus. How many neutrons does it have?

Answer:

The atomic mass of Helium = 4 u
No. of protons = 2

As atomic mass = no. of protons + no. of neutrons
No. of neutrons = At. mass - no. of protons
= 4 - 2

= 2

Hence Heium atom has 2 neutrons.

Solutions for NCERT class 9 science chapter 4 Structure of the Atom

Topic 4.3 How are electrons distributed in different orbits(shells)?

Q. 1. Write the distribution of electrons in carbon and sodium atoms.

Answer:

Number of electrons in carbon atom = 6

Number of electrons in sodium atom = 11

Electron Distribution:

Element First Orbit or K -shell Second Orbit or L-shell Third Orbit or M-shell
Carbon 2 4 0
Sodium 2 8 1


Q. 2. If K and L shells of an atom are full, then what would be the total number of electrons in the atom?

Answer:

Maximum Number of electrons in K-shell = 2

Maximum Number of electrons in L-shell = 8

The total no. of electrons in the atom = 2 + 8

= 10

If K and L shells of an atom are full, then the total number of electrons in the atom will be 10.

NCERT solutions for class 9 science chapter 4 Structure of the Atom

Topic 4.4 Valency

Q. 1. How will you find the valency of chlorine, sulphur and magnesium?

Answer:

Valancy is basically the minimum number of the electron we have to add or remove such that every shell in the atom is completely filled.

Mathematically,

when the outermost shell of an atom contains 4 or less than 4 electrons, its valency is equal to the number of valence electrons in the outermost shell and when the outermost shell contains more than 4 electrons, the valency of the atom is equal to 8 - no. of valence electrons in the atom.

Chlorine :

Atomic No. of Cl = 17

Its electronic configuration = 2, 8, 7

Valency of Cl = 8 - 7 = 1

Sulphur :

Atomic no. of S = 16

Its electronic configuration = 2, 8, 6

Valency of S = 8 - 6 = 2

Magnesium:

Atomic no. of Mg = 12

Its electronic configuration = 2, 8, 2

Valency of Mg = 2

NCERT textbook solutions for class 9 science chapter 4 Structure of the Atom

Topic 4.5 Atomic number and Mass number

Q. 1.(i) If the number of electrons in an atom is 8 and the number of protons is also 8, then

(i) what is the atomic number of the atom?

Answer:

Given,

Number of electrons in the atom = 8

Number of proton in the atom = 8

The atomic number of an atom is equal to the number of proton in that atom. hence the atomic number of the given atom is 8.

Q. 1. (ii) If the number of electrons in an atom is 8 and the number of protons is also 8, then

(ii) what is the charge on the atom?

Answer:

In the given atom, the total number of positive charges is equal to the total number of negative charge.

Number of Protons (8) = Number of electrons (8)

They both will neutralize each other. So, the atom will not possess any charge.

Q. 2. With the help of Table 4.1, find out the mass number of oxygen and sulfur atom.

compositions%20of%20Atom

Answer:

For Oxygen:

Number of protons = 8

Number of electrons = 8

Mass number = Number of Protons + Number of neutrons

= 8 + 8

= 16

Hence mass number for Oxygen is 16.

For Sulphur:

Number of protons = 16

Number of electrons = 16

Mass number = Number of Protons + Number of neutrons

= 16 + 16

= 32

Hence Mass number for Sulphur is 32.

CBSE NCERT solutions for class 9 science chapter 4 Structure of the Atom

Topic 4.6 Isotopes

Q. 1. For the symbol H,D and T tabulate three sub-atomic particles found in each of them.

Answer:

H, D, and T are the three isotopes of hydrogen with the same atomic number and different mass numbers of 1, 2 and 3 respectively.

Element Symbol Number of Electrons Number of Protons Number of Neutrons
Hydrogen H 1 1 0
Deuterium D 1 1 1
Tritium T 1 1 2


Q. 2. Write the electronic configuration of any one pair of isotopes and isobars.

Answer:

Isotopes :

Isotopes are the atoms with the same number of proton and different atomic mass. The difference in atomic mass arises due to the different number of neutrons present in the atom.

Some Examples of Isotopes are :

1. ^{12}C_6 and ^{14}C_6 ,

2. ^{35}Cl_{17} and ^{37}Cl_{17} .

Isobar:

Isobars are the atom with the same atomic mass and different atomic number.

Some example of Isobars are :

1. ^{40}Ca_{20} and ^{40}Ar_{18}

2. ^{22}Ne_{10} and ^{22}Na_{11}

NCERT solutions for class 9 science chapter 4 Structure of the Atom: Solved Exercise Questions

Q. 1. Compare the properties of electrons, protons, and neutrons.

Answer:

The Comparison of Properties between Electron, Proton, and Neutron:

Properties Electrons Protons Neutrons
Charge Negatively charged Positively charged No charge
Weight Negligible 1 a.m.u 1 a.m.u
Location in atom Outside the nucleus Inside the nucleus Inside the nucleus
Reaction with a charged particle Attracts positive charge Attracts negative charge gives no reaction to any charge

Q. 2. What are the limitations of J.J. Thomson’s model of the atom?

Answer:

The limitations of J.J. Thomson’s model of the atom are:

1. Thomson's model of the atom could not explain the results of alpha particle scattering experiment carried out by Rutherford. this model failed to depict why most of the alpha particle passes through gold foil and why some of them got diverted in different angles and some of them rebounded and returned back to their paths.

2. It was solely based on the imagination and did not have any experimental evidence.

Q. 3. What are the limitations of Rutherford’s model of the atom?

Answer:

The limitations of Rutherford's model of the atom is that It does not explain the stability of the atom. As we know now, when charged bodies move in a circular motion, they emit radiations.

This means that the electrons revolving around the nucleus (as suggested by Rutherford) would lose energy and come closer and closer to the nucleus, and a stage will come when they would finally merge into the nucleus.

This makes the atom unstable, which is clearly not the case. The electrons do not fall into the nucleus, atoms are very stable and do not collapse on their own.

Q. 4. Describe Bohr’s model of the atom.

Answer:

In order to overcome the objections raised against Rutherford's model of the atom, Neils Bohr put forward his model of the atom. According to Bohr's model of the atom,
1. An atom holds the nucleus in the center. the whole mass of the atom is concentrated at the nucleus.

2. The negatively charged particle revolves around the nucleus in definite circular paths known as orbits or which are designated as K, L, M, N, etc. or numbered as n = 1, 2, 3, 4, etc. (outward from the nucleus).

3. While revolving in discrete orbits, the electrons do not radiate energy. But when an electron jumps from one energy level to another, the energy of the atom changes.


1651477380172

Q. 5. Compare all the proposed models of an atom given in this chapter.

Answer:

Comparison of different proposed Model:

Feature Thomson's Model Rutherford's Model Bohr's Model
Positive Charge The Positive charge is distributed in Sphere The positive charge is concentrated at the core of the atom, which is called the nucleus The positive charge is present in the core of the atom, called nucleus.
Negative Charge The electrons are embedded in the positively charged sphere of an atom, like the seeds in a watermelon. The nucleus is surrounded by electrons, and the electrons and the nucleus are held together by the electrostatic force of attraction The electrons move in discrete orbits, and each orbit is associated with a definite amount of energy.
Limitation This model could not explain the results of an alpha particle scattering experiment This model could not explain the stability of the atom. This model perfectly explains the stability of an atom
Diagrammatic representation 165147743230716514774707851651477487143


Q. 6. Summarise the rules for the writing of the distribution of electrons in various shells for the first eighteen elements.

Answer:

The Bohr and Bury scheme for the distribution of electrons in an atom is based on the following rules :
1. The maximum number of electrons that a shell can have is represented by 2n^2 , where n is the quantum number of that particular energy shell. Thus, the maximum number of electrons in the first four shells are :
1st (K) shell 2 x 1^2 = 2
2nd (L) shell 2 x 2^2 = 8
3rd (M) shell 2 x 3^2 = 18
4th (N) shell 2 x 4^2 = 32

2. The outermost shell, which is also called valence shell, can have a maximum of 8 electrons.

3. If permitted by rule 1, The shell inner to the outermost shell (the second last shell ) can accommodate a maximum of 18 electrons.

4. Electrons are not taken in unless the inner shells are filled, i.e., the shells are filled in a step-wise manner.

Q. 7. Define valency by taking examples of silicon and oxygen.

Answer:

The definite combining capacity of an atom of an element, in which electrons are lost, gained or shared with other atoms to complete the octave in the outermost shell is defined as valency.

In other words,

Valancy is basically the minimum number of the electron we have to add or remove from or in the outermost shell such that every shell in the atom is completely filled.

And Mathematically,

when the outermost shell of an atom contains 4 or less than 4 electrons, its valency is equal to the number of valence electrons in the outermost shell and when the outermost shell contains more than 4 electrons, the valency of the atom is equal to 8 - no. of valence electrons in the atom.

The valency of Silicon:

Atomic number = 14

Distribution of electron :

K = 2

L = 8

M = 4

Number of electrons in outermost shell = 4

Valency = 8 - 4 = 4.

The valency of Oxygen:

Atomic number = 8

Distribution of electrons:

K = 2

L = 6

The number of electron in outermost shell = 6

Valency = 8 - 6 = 2

Q. 8.(i) Explain with examples

(i) Atomic number,

Answer:

Atomic Number :

An atomic number of an atom is the total number of protons present within the nucleus of an atom is known as the atomic number. it is denoted by symbol Z.

Example: As the Oxygen atom has 8 protons in its nucleus, its atomic number is 8.

Q. 8.(ii) Explain with examples

(ii) Mass number,

Answer:

Mass Number :

The mass number of an atom is the sum total of the masses of all the nucleons present in the nucleus of an atom, i.e.,
Mass Number = No. of Protons + No. of Neutrons

It is denoted by A.


Example: As a sodium atom has 11 protons and 12 neutrons in its nucleus,

So, it's mass number = 11 + 12 = 23.

Q. 8.(iii) Explain with examples

(iii) Isotopes

Answer:

Isotopes:

Isotopes are the atoms of the same element having the same atomic number but a different mass number.

Example: Carbon molecule exists as ^{12}C_6 and ^{14}C_6 .

Q. 8.(iv) Explain with examples

(iv) Isobars.

Answer:

Isobar:

Isobars are the atoms of different elements having the same mass number but different atomic numbers.


Example: ^{40}Ca_{20} and ^{40}Ar_{18} . Mass numbers of calcium and argon atoms have different atomic numbers (20 and 18 ) but the same mass number 40.

Two uses of isotopes are:

(i) An isotope of uranium is used as fuel in nuclear reactors.

(ii) An isotope of cobalt is used in the treatment of cancer.

Q. 9. Na^{+} has completely filled K and L shells. Explain.

Answer:

The atomic number of Na = 11

No. of electrons in Na atom = 11

In Na^{+} ,the positive charge is obtained due to the loss of one electron from the M shell of Na atom.

So, No. of electrons in Na + ion = 11 -1 = 10

Hence, electronic configuration of Na + = 2, 8

In Na + , K and L shells are completely filled since K shell can have a maximum of 2 electrons and L shell can have a maximum of 8 electrons.

Q. 11. The average atomic mass of a sample of an element X is 16.2\; u . What are the percentages of isotopes _{8}^{16}\textrm{X} and _{8}^{18}\textrm{X} in the sample?

Answer:

Given, the average atomic mass of a sample of an element X is 16.2\; u .

Two isotopes of element = _{8}^{16}\textrm{X} and _{8}^{18}\textrm{X}

Now, Let's percent of isotope _{8}^{16}\textrm{X} be x and percent of _{8}^{18}\textrm{X} be 100 - x

So, According to the question,

Average Atomic Mass :

16.2=16\times\frac{x}{100}+18\times\frac{100-x}{100}

16.2=\frac{16x}{100}+18-\frac{18x}{100}

-1.8=-\frac{2x}{100}

2x=180

x=90

Hence the percentage of isotope _{8}^{16}\textrm{X} is 90 % and thepercentage isotope _{8}^{16}\textrm{X} is 10%.

Q. 12. If Z=3 , what would be the valency of the element? Also, name the element.

Answer:

Given

the Atomic number, Z = 3

Distribution of electrons :

K = 2,

L = 1
So, Valency = 1 .

The element with atomic number 3 is lithium.

Q. 13. Composition of the nuclei of two atomic species X and Y are given as under

X Y

Protons = 6 6

Neutrons = 6 8

Give the mass numbers of X and Y . What is the relation between the two species?

Answer:

As we know,

the mass number of an atom = No. of protons + No. of Neutrons

So,

The mass number of X = No. of protons of X + No. of Neutrons of X

= 6 + 6

= 12

The mass number of Y = No. of protons of Y + No. of Neutrons of Y

= 6 + 8

= 14

As both X and Y have the same atomic number (6) but different numbers (i.e., 12 and 14 respectively), they are isotopes.

Q. 14. For the following statements, write T for True and F for False.

(a) J.J. Thomson proposed that the nucleus of an atom contains only nucleons.

(b) A neutron is formed by an electron and a proton combining together. Therefore, it is neutral.

(c) The mass of an electron is about 1 2000 times that of a proton.

(d) An isotope of iodine is used for making tincture iodine, which is used as a medicine.

Put a tick against correct choice and cross (×) against wrong choice in questions 15, 16 and 17

Answer:

(a) The statement is False.
(b) The statement is False.
(c) The statement is True.
(d) The statement is True.

Q. 15. Rutherford’s alpha-particle scattering experiment was responsible for the discovery of

(a) Atomic Nucleus

(b) Electron

(c) Proton

(d) Neutron

Answer:

Rutherford’s alpha-particle scattering experiment was responsible for the discovery of the Atomic Nucleus.

Hence, option (a) is the correct answer.

Q. 16. Isotopes of an element have

(a) the same physical properties

(b) different chemical properties

(c) different number of neutrons

(d) different atomic numbers

Answer:

Isotopes of an element have a different number of neutrons.

Hence option (c) is correct.

Q. 17. A Number of valence electrons in Cl^{-} ion are:

(a) 16

(b) 8

(c) 17

(d) 18

Answer:

The Electronic configuration of Cl^{-} ion is :

K = 2

L = 8

M = 8

Hence Number of valance electron in Cl^{-} ion = 8.

Hence, option (b) is the correct answer.

Q. 18. Which one of the following is a correct electronic configuration of sodium?

(a) 2,8

(b) 8,2,1

(c) 2,1,8

(d) 2,8,1.

Answer:

The atomic number of sodium = 11

The electronic configuration of the sodium :

K = 2

L = 8

M = 1

Hence, option (d) is correct.

Q. 19. Complete the following table.

Answer:

Atomic NumberMass NumberNumber of NeutronsNumber of ProtonsNumber of ElectronsNumber of Atomic Species
9-10---
1632---Sulphur
-24-12--
-2-1--
-1010-

First row:

atomic number = 9

so, the element is Fluorine.

Atomic no. = No. of protons = no. of electrons = 9

Mass number = no. of protons + no. of neutrons = 9 + 10 = 19

Second row:

Since atomic no. is 16 so, no. of protons = no. of electrons = 16

No. of neutrons = Mass no. - no. of protons = 32 - 16 = 16

Third row:

No. of protons = Atomic no. = 12

So, the element is Magnesium.

No. of electrons = no. of protons = 12

No. of neutrons = Mass no. - no. of protons = 24 - 12 = 12

Fourth row:

No. of protons = Atomic no. = 1

So, the element is Deuterium.

No. of electrons = no. of protons = 1

No. of neutrons = Mass no. - no. of protons = 2 - 1 = 1

Fifth row:

No. of protons = Atomic no. = 1

The element is Protium since the mass number is 1.

So the Table becomes,

Atomic number mass number Number of neutrons Number of protons Number of electrons Name of the element
9 19 10 9 9 Fluorine
16 32 16 16 16 Sulfur
12 24 12 12 12 Magnesium
1 2 1 1 1 Deuterium
1 1 1 1 0 Hydrogen ion


NCERT Solutions for Class 9 Science- Chapter Wise

Chapter No.
Chapter Name
Chapter 1
Matter in Our Surroundings
Chapter 2
Is Matter Around Us Pure
Chapter 3
Atoms and Molecules
Chapter 4
Structure of The Atom
Chapter 5
The Fundamental Unit of Life
Chapter 6
Tissues
Chapter 7
Diversity in Living Organisms
Chapter 8
Motion
Chapter 9
Force and Laws of Motion
Chapter 10
Gravitation
Chapter 11
Work and Energy
Chapter 12
Sound
Chapter 13
Why Do We Fall ill?
Chapter 14
Natural Resources
Chapter 15
Improvement in Food Resources

NCERT Solutions for Class 9 Science: Important Formulas and Diagrams + eBook link

Formulas are essential tools for solving numerical problems and gaining a detailed understanding of a chapter. Here are some important formulas for the science chapter 4 class 9, which will enable you to solve questions smoothly and efficiently.

  • Maximum number of electrons in different shells

According to the Bohr model of the atom, the maximum number of electrons that can occupy a shell is given by the formula 2n2, where n represents the shell number. The first shell (n = 1) can hold a maximum of 2 electrons, the second shell (n = 2) can hold a maximum of 8 electrons, and so on.

  • Average atomic mass

Average atomic mass = (M1× P1) + (M2 × P2) + ... + (Mn × Pn)

Where:

M1, M2 ..., and Mn represent the individual atomic masses of the isotopes of the element.

P1, P2 ..., and Pn represent their respective natural abundances as decimal fractions or percentages (converted to decimal form).

For a comprehensive collection of class 9 science chapter-wise formulas, a downloadable handbook is available at the provided link. Students can utilize this resource to access formulas for each chapter, aiding them in solving questions, revising concepts, and collaborating with their peers effectively. This handbook serves as a valuable tool for enhancing understanding and achieving success in science examinations.

NCERT Solutions for Class 9 Science Chapter 4 Structure of the Atom - Important Topics

The important topics for class 9 chapter 4 science, "Structure of the Atom," are highly significant for exams and school tests. By focusing on these key areas during revision, students can efficiently review the chapter and consolidate their understanding. Here are the important topics for quick revision:

  • Introduction to atoms: Made up of protons, neutrons, and electrons, atoms are the fundamental units of matter.
  • Charged particles in matter: Matter is composed of positively charged protons, neutral neutrons, and negatively charged electrons.
  • The structure of an atom: Protons and neutrons make up the core nucleus of an atom, which is encircled by orbiting electrons.
  • Thomson's model of the atom: Also known as the "plum pudding" model, Thomson proposed that an atom is a positively charged mass with embedded negatively charged electrons.
  • Rutherford's model of the atom: Rutherford's model suggests that atoms have a tiny, positively charged nucleus at the centre, with electrons orbiting around it.
  • Bohr's model of the atom: Bohr proposed that electrons occupy specific energy levels or orbit around the nucleus, and they jump between these levels by absorbing or emitting energy.
  • Electron distribution in different orbits: Electrons are arranged in different energy levels or electron shells, with lower energy levels closer to the nucleus.

Key features of NCERT solutions for class 9 science chapter 4 Structure

  • Expertly Crafted Solutions: The NCERT class 9 science chapter 4 question answers are created by subject matter experts, ensuring accuracy and reliability.
  • Error-Free Solutions: The class 9 science chapter 4 solutions are thoroughly reviewed to reduce errors and give students solid solutions.
  • Simple Language: The CBSE NCERT solutions for class 9 science chapter 4 Structure of the Atom are explained in a simple and easy-to-understand language, making it accessible for students of all proficiency levels.
  • Comprehensive Explanation: The solutions provide a comprehensive explanation of the concepts, helping students grasp the underlying principles effectively.
  • Step-by-Step Approach: The solutions are presented in a step-by-step manner, taking students through the process of problem-solving and enhancing their understanding.
  • Clarity in Concepts: The solutions clarify the fundamental concepts related to the structure of atoms, leaving no room for confusion.
  • Alignment with NCERT Textbook: The class 9 science chapter 4 exercise question answer are aligned with the NCERT textbook, ensuring that students cover the required syllabus and meet the examination requirements.

Also Check -

NCERT Books and NCERT Syllabus :

NCERT Solutions for Class 9 - Subject Wise

NCERT Science Exemplar Solutions Class 9 - Chapter Wise

Frequently Asked Question (FAQs)

1. What are the important topics coverd under Class 9 Science NCERT syllabus chapter 4?

The main topics covered in NCERT text book for Class 9 Science chapter 4 are-

  • Concept of Charged Particles in Matter 
  • Different Models of The Atom
  • Neutrons
  • How Are Electrons Distributed in Different Orbits
  • Valency, Atomic Number and Mass Number.
2. What are the main components of an atom?

The main components of an atom are protons, neutrons, and electrons. Protons and neutrons are located in the nucleus, while electrons orbit around the nucleus.

3. How do isotopes differ from each other?

Isotopes are atoms of the same element that have the same number of protons but differ in the number of neutrons. This results in isotopes having different mass numbers.

4. What are the different atomic models discussed in this chapter?

The chapter discusses several atomic models, including Thomson's plum pudding model, Rutherford's nuclear model, and Bohr's model of the atom.

5. How can I effectively revise this chapter for exams?

To revise the chapter effectively, focus on understanding the key concepts, practice numerical problems, and review the important formulas related to atomic structure. Additionally, refer to the NCERT textbook, study guides, and solved examples for comprehensive preparation.

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0.34\; J

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0.16\; J

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1.00\; J

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0.67\; J

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2.45×10−3 kg

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 6.45×10−3 kg

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 9.89×10−3 kg

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12.89×10−3 kg

 

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2,000 \; J - 5,000\; J

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200 \, \, J - 500 \, \, J

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2\times 10^{5}J-3\times 10^{5}J

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20,000 \, \, J - 50,000 \, \, J

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

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K/2\,

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\; K\;

Option 3)

zero\;

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K/4

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced

Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

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67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

Option 2)

3.125 × 10-2

Option 3)

1.25 × 10-2

Option 4)

2.5 × 10-2

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

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increase two fold

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remain unchanged

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be a function of the molecular mass of the substance.

With increase of temperature, which of these changes?

Option 1)

Molality

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Weight fraction of solute

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Fraction of solute present in water

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Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

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twice that in 60 g carbon

Option 2)

6.023 × 1022

Option 3)

half that in 8 g He

Option 4)

558.5 × 6.023 × 1023

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

Option 2)

more than 3 but less than 6

Option 3)

more than 6 but less than 9

Option 4)

more than 9

Bio Medical Engineer

The field of biomedical engineering opens up a universe of expert chances. An Individual in the biomedical engineering career path work in the field of engineering as well as medicine, in order to find out solutions to common problems of the two fields. The biomedical engineering job opportunities are to collaborate with doctors and researchers to develop medical systems, equipment, or devices that can solve clinical problems. Here we will be discussing jobs after biomedical engineering, how to get a job in biomedical engineering, biomedical engineering scope, and salary. 

4 Jobs Available
Data Administrator

Database professionals use software to store and organise data such as financial information, and customer shipping records. Individuals who opt for a career as data administrators ensure that data is available for users and secured from unauthorised sales. DB administrators may work in various types of industries. It may involve computer systems design, service firms, insurance companies, banks and hospitals.

4 Jobs Available
Ethical Hacker

A career as ethical hacker involves various challenges and provides lucrative opportunities in the digital era where every giant business and startup owns its cyberspace on the world wide web. Individuals in the ethical hacker career path try to find the vulnerabilities in the cyber system to get its authority. If he or she succeeds in it then he or she gets its illegal authority. Individuals in the ethical hacker career path then steal information or delete the file that could affect the business, functioning, or services of the organization.

3 Jobs Available
Data Analyst

The invention of the database has given fresh breath to the people involved in the data analytics career path. Analysis refers to splitting up a whole into its individual components for individual analysis. Data analysis is a method through which raw data are processed and transformed into information that would be beneficial for user strategic thinking.

Data are collected and examined to respond to questions, evaluate hypotheses or contradict theories. It is a tool for analyzing, transforming, modeling, and arranging data with useful knowledge, to assist in decision-making and methods, encompassing various strategies, and is used in different fields of business, research, and social science.

3 Jobs Available
Geothermal Engineer

Individuals who opt for a career as geothermal engineers are the professionals involved in the processing of geothermal energy. The responsibilities of geothermal engineers may vary depending on the workplace location. Those who work in fields design facilities to process and distribute geothermal energy. They oversee the functioning of machinery used in the field.

3 Jobs Available
Remote Sensing Technician

Individuals who opt for a career as a remote sensing technician possess unique personalities. Remote sensing analysts seem to be rational human beings, they are strong, independent, persistent, sincere, realistic and resourceful. Some of them are analytical as well, which means they are intelligent, introspective and inquisitive. 

Remote sensing scientists use remote sensing technology to support scientists in fields such as community planning, flight planning or the management of natural resources. Analysing data collected from aircraft, satellites or ground-based platforms using statistical analysis software, image analysis software or Geographic Information Systems (GIS) is a significant part of their work. Do you want to learn how to become remote sensing technician? There's no need to be concerned; we've devised a simple remote sensing technician career path for you. Scroll through the pages and read.

3 Jobs Available
Geotechnical engineer

The role of geotechnical engineer starts with reviewing the projects needed to define the required material properties. The work responsibilities are followed by a site investigation of rock, soil, fault distribution and bedrock properties on and below an area of interest. The investigation is aimed to improve the ground engineering design and determine their engineering properties that include how they will interact with, on or in a proposed construction. 

The role of geotechnical engineer in mining includes designing and determining the type of foundations, earthworks, and or pavement subgrades required for the intended man-made structures to be made. Geotechnical engineering jobs are involved in earthen and concrete dam construction projects, working under a range of normal and extreme loading conditions. 

3 Jobs Available
Cartographer

How fascinating it is to represent the whole world on just a piece of paper or a sphere. With the help of maps, we are able to represent the real world on a much smaller scale. Individuals who opt for a career as a cartographer are those who make maps. But, cartography is not just limited to maps, it is about a mixture of art, science, and technology. As a cartographer, not only you will create maps but use various geodetic surveys and remote sensing systems to measure, analyse, and create different maps for political, cultural or educational purposes.

3 Jobs Available
Budget Analyst

Budget analysis, in a nutshell, entails thoroughly analyzing the details of a financial budget. The budget analysis aims to better understand and manage revenue. Budget analysts assist in the achievement of financial targets, the preservation of profitability, and the pursuit of long-term growth for a business. Budget analysts generally have a bachelor's degree in accounting, finance, economics, or a closely related field. Knowledge of Financial Management is of prime importance in this career.

4 Jobs Available
Data Analyst

The invention of the database has given fresh breath to the people involved in the data analytics career path. Analysis refers to splitting up a whole into its individual components for individual analysis. Data analysis is a method through which raw data are processed and transformed into information that would be beneficial for user strategic thinking.

Data are collected and examined to respond to questions, evaluate hypotheses or contradict theories. It is a tool for analyzing, transforming, modeling, and arranging data with useful knowledge, to assist in decision-making and methods, encompassing various strategies, and is used in different fields of business, research, and social science.

3 Jobs Available
Product Manager

A Product Manager is a professional responsible for product planning and marketing. He or she manages the product throughout the Product Life Cycle, gathering and prioritising the product. A product manager job description includes defining the product vision and working closely with team members of other departments to deliver winning products.  

3 Jobs Available
Underwriter

An underwriter is a person who assesses and evaluates the risk of insurance in his or her field like mortgage, loan, health policy, investment, and so on and so forth. The underwriter career path does involve risks as analysing the risks means finding out if there is a way for the insurance underwriter jobs to recover the money from its clients. If the risk turns out to be too much for the company then in the future it is an underwriter who will be held accountable for it. Therefore, one must carry out his or her job with a lot of attention and diligence.

3 Jobs Available
Finance Executive
3 Jobs Available
Operations Manager

Individuals in the operations manager jobs are responsible for ensuring the efficiency of each department to acquire its optimal goal. They plan the use of resources and distribution of materials. The operations manager's job description includes managing budgets, negotiating contracts, and performing administrative tasks.

3 Jobs Available
Investment Director

An investment director is a person who helps corporations and individuals manage their finances. They can help them develop a strategy to achieve their goals, including paying off debts and investing in the future. In addition, he or she can help individuals make informed decisions.

2 Jobs Available
Welding Engineer

Welding Engineer Job Description: A Welding Engineer work involves managing welding projects and supervising welding teams. He or she is responsible for reviewing welding procedures, processes and documentation. A career as Welding Engineer involves conducting failure analyses and causes on welding issues. 

5 Jobs Available
Transportation Planner

A career as Transportation Planner requires technical application of science and technology in engineering, particularly the concepts, equipment and technologies involved in the production of products and services. In fields like land use, infrastructure review, ecological standards and street design, he or she considers issues of health, environment and performance. A Transportation Planner assigns resources for implementing and designing programmes. He or she is responsible for assessing needs, preparing plans and forecasts and compliance with regulations.

3 Jobs Available
Plumber

An expert in plumbing is aware of building regulations and safety standards and works to make sure these standards are upheld. Testing pipes for leakage using air pressure and other gauges, and also the ability to construct new pipe systems by cutting, fitting, measuring and threading pipes are some of the other more involved aspects of plumbing. Individuals in the plumber career path are self-employed or work for a small business employing less than ten people, though some might find working for larger entities or the government more desirable.

2 Jobs Available
Construction Manager

Individuals who opt for a career as construction managers have a senior-level management role offered in construction firms. Responsibilities in the construction management career path are assigning tasks to workers, inspecting their work, and coordinating with other professionals including architects, subcontractors, and building services engineers.

2 Jobs Available
Urban Planner

Urban Planning careers revolve around the idea of developing a plan to use the land optimally, without affecting the environment. Urban planning jobs are offered to those candidates who are skilled in making the right use of land to distribute the growing population, to create various communities. 

Urban planning careers come with the opportunity to make changes to the existing cities and towns. They identify various community needs and make short and long-term plans accordingly.

2 Jobs Available
Highway Engineer

Highway Engineer Job Description: A Highway Engineer is a civil engineer who specialises in planning and building thousands of miles of roads that support connectivity and allow transportation across the country. He or she ensures that traffic management schemes are effectively planned concerning economic sustainability and successful implementation.

2 Jobs Available
Environmental Engineer

Individuals who opt for a career as an environmental engineer are construction professionals who utilise the skills and knowledge of biology, soil science, chemistry and the concept of engineering to design and develop projects that serve as solutions to various environmental problems. 

2 Jobs Available
Naval Architect

A Naval Architect is a professional who designs, produces and repairs safe and sea-worthy surfaces or underwater structures. A Naval Architect stays involved in creating and designing ships, ferries, submarines and yachts with implementation of various principles such as gravity, ideal hull form, buoyancy and stability. 

2 Jobs Available
Orthotist and Prosthetist

Orthotists and Prosthetists are professionals who provide aid to patients with disabilities. They fix them to artificial limbs (prosthetics) and help them to regain stability. There are times when people lose their limbs in an accident. In some other occasions, they are born without a limb or orthopaedic impairment. Orthotists and prosthetists play a crucial role in their lives with fixing them to assistive devices and provide mobility.

6 Jobs Available
Veterinary Doctor
5 Jobs Available
Pathologist

A career in pathology in India is filled with several responsibilities as it is a medical branch and affects human lives. The demand for pathologists has been increasing over the past few years as people are getting more aware of different diseases. Not only that, but an increase in population and lifestyle changes have also contributed to the increase in a pathologist’s demand. The pathology careers provide an extremely huge number of opportunities and if you want to be a part of the medical field you can consider being a pathologist. If you want to know more about a career in pathology in India then continue reading this article.

5 Jobs Available
Speech Therapist
4 Jobs Available
Gynaecologist

Gynaecology can be defined as the study of the female body. The job outlook for gynaecology is excellent since there is evergreen demand for one because of their responsibility of dealing with not only women’s health but also fertility and pregnancy issues. Although most women prefer to have a women obstetrician gynaecologist as their doctor, men also explore a career as a gynaecologist and there are ample amounts of male doctors in the field who are gynaecologists and aid women during delivery and childbirth. 

4 Jobs Available
Oncologist

An oncologist is a specialised doctor responsible for providing medical care to patients diagnosed with cancer. He or she uses several therapies to control the cancer and its effect on the human body such as chemotherapy, immunotherapy, radiation therapy and biopsy. An oncologist designs a treatment plan based on a pathology report after diagnosing the type of cancer and where it is spreading inside the body.

3 Jobs Available
Audiologist

The audiologist career involves audiology professionals who are responsible to treat hearing loss and proactively preventing the relevant damage. Individuals who opt for a career as an audiologist use various testing strategies with the aim to determine if someone has a normal sensitivity to sounds or not. After the identification of hearing loss, a hearing doctor is required to determine which sections of the hearing are affected, to what extent they are affected, and where the wound causing the hearing loss is found. As soon as the hearing loss is identified, the patients are provided with recommendations for interventions and rehabilitation such as hearing aids, cochlear implants, and appropriate medical referrals. While audiology is a branch of science that studies and researches hearing, balance, and related disorders.

3 Jobs Available
Hospital Administrator

The hospital Administrator is in charge of organising and supervising the daily operations of medical services and facilities. This organising includes managing of organisation’s staff and its members in service, budgets, service reports, departmental reporting and taking reminders of patient care and services.

2 Jobs Available
Actor

For an individual who opts for a career as an actor, the primary responsibility is to completely speak to the character he or she is playing and to persuade the crowd that the character is genuine by connecting with them and bringing them into the story. This applies to significant roles and littler parts, as all roles join to make an effective creation. Here in this article, we will discuss how to become an actor in India, actor exams, actor salary in India, and actor jobs. 

4 Jobs Available
Acrobat

Individuals who opt for a career as acrobats create and direct original routines for themselves, in addition to developing interpretations of existing routines. The work of circus acrobats can be seen in a variety of performance settings, including circus, reality shows, sports events like the Olympics, movies and commercials. Individuals who opt for a career as acrobats must be prepared to face rejections and intermittent periods of work. The creativity of acrobats may extend to other aspects of the performance. For example, acrobats in the circus may work with gym trainers, celebrities or collaborate with other professionals to enhance such performance elements as costume and or maybe at the teaching end of the career.

3 Jobs Available
Video Game Designer

Career as a video game designer is filled with excitement as well as responsibilities. A video game designer is someone who is involved in the process of creating a game from day one. He or she is responsible for fulfilling duties like designing the character of the game, the several levels involved, plot, art and similar other elements. Individuals who opt for a career as a video game designer may also write the codes for the game using different programming languages.

Depending on the video game designer job description and experience they may also have to lead a team and do the early testing of the game in order to suggest changes and find loopholes.

3 Jobs Available
Radio Jockey

Radio Jockey is an exciting, promising career and a great challenge for music lovers. If you are really interested in a career as radio jockey, then it is very important for an RJ to have an automatic, fun, and friendly personality. If you want to get a job done in this field, a strong command of the language and a good voice are always good things. Apart from this, in order to be a good radio jockey, you will also listen to good radio jockeys so that you can understand their style and later make your own by practicing.

A career as radio jockey has a lot to offer to deserving candidates. If you want to know more about a career as radio jockey, and how to become a radio jockey then continue reading the article.

3 Jobs Available
Choreographer

The word “choreography" actually comes from Greek words that mean “dance writing." Individuals who opt for a career as a choreographer create and direct original dances, in addition to developing interpretations of existing dances. A Choreographer dances and utilises his or her creativity in other aspects of dance performance. For example, he or she may work with the music director to select music or collaborate with other famous choreographers to enhance such performance elements as lighting, costume and set design.

2 Jobs Available
Videographer
2 Jobs Available
Multimedia Specialist

A multimedia specialist is a media professional who creates, audio, videos, graphic image files, computer animations for multimedia applications. He or she is responsible for planning, producing, and maintaining websites and applications. 

2 Jobs Available
Social Media Manager

A career as social media manager involves implementing the company’s or brand’s marketing plan across all social media channels. Social media managers help in building or improving a brand’s or a company’s website traffic, build brand awareness, create and implement marketing and brand strategy. Social media managers are key to important social communication as well.

2 Jobs Available
Copy Writer

In a career as a copywriter, one has to consult with the client and understand the brief well. A career as a copywriter has a lot to offer to deserving candidates. Several new mediums of advertising are opening therefore making it a lucrative career choice. Students can pursue various copywriter courses such as Journalism, Advertising, Marketing Management. Here, we have discussed how to become a freelance copywriter, copywriter career path, how to become a copywriter in India, and copywriting career outlook. 

5 Jobs Available
Journalist

Careers in journalism are filled with excitement as well as responsibilities. One cannot afford to miss out on the details. As it is the small details that provide insights into a story. Depending on those insights a journalist goes about writing a news article. A journalism career can be stressful at times but if you are someone who is passionate about it then it is the right choice for you. If you want to know more about the media field and journalist career then continue reading this article.

3 Jobs Available
Publisher

For publishing books, newspapers, magazines and digital material, editorial and commercial strategies are set by publishers. Individuals in publishing career paths make choices about the markets their businesses will reach and the type of content that their audience will be served. Individuals in book publisher careers collaborate with editorial staff, designers, authors, and freelance contributors who develop and manage the creation of content.

3 Jobs Available
Vlogger

In a career as a vlogger, one generally works for himself or herself. However, once an individual has gained viewership there are several brands and companies that approach them for paid collaboration. It is one of those fields where an individual can earn well while following his or her passion. 

Ever since internet costs got reduced the viewership for these types of content has increased on a large scale. Therefore, a career as a vlogger has a lot to offer. If you want to know more about the Vlogger eligibility, roles and responsibilities then continue reading the article. 

3 Jobs Available
Editor

Individuals in the editor career path is an unsung hero of the news industry who polishes the language of the news stories provided by stringers, reporters, copywriters and content writers and also news agencies. Individuals who opt for a career as an editor make it more persuasive, concise and clear for readers. In this article, we will discuss the details of the editor's career path such as how to become an editor in India, editor salary in India and editor skills and qualities.

3 Jobs Available
Linguist

Linguistic meaning is related to language or Linguistics which is the study of languages. A career as a linguistic meaning, a profession that is based on the scientific study of language, and it's a very broad field with many specialities. Famous linguists work in academia, researching and teaching different areas of language, such as phonetics (sounds), syntax (word order) and semantics (meaning). 

Other researchers focus on specialities like computational linguistics, which seeks to better match human and computer language capacities, or applied linguistics, which is concerned with improving language education. Still, others work as language experts for the government, advertising companies, dictionary publishers and various other private enterprises. Some might work from home as freelance linguists. Philologist, phonologist, and dialectician are some of Linguist synonym. Linguists can study French, German, Italian

2 Jobs Available
Public Relation Executive
2 Jobs Available
Travel Journalist

The career of a travel journalist is full of passion, excitement and responsibility. Journalism as a career could be challenging at times, but if you're someone who has been genuinely enthusiastic about all this, then it is the best decision for you. Travel journalism jobs are all about insightful, artfully written, informative narratives designed to cover the travel industry. Travel Journalist is someone who explores, gathers and presents information as a news article.

2 Jobs Available
Welding Engineer

Welding Engineer Job Description: A Welding Engineer work involves managing welding projects and supervising welding teams. He or she is responsible for reviewing welding procedures, processes and documentation. A career as Welding Engineer involves conducting failure analyses and causes on welding issues. 

5 Jobs Available
QA Manager
4 Jobs Available
Quality Controller

A quality controller plays a crucial role in an organisation. He or she is responsible for performing quality checks on manufactured products. He or she identifies the defects in a product and rejects the product. 

A quality controller records detailed information about products with defects and sends it to the supervisor or plant manager to take necessary actions to improve the production process.

3 Jobs Available
Product Manager

A Product Manager is a professional responsible for product planning and marketing. He or she manages the product throughout the Product Life Cycle, gathering and prioritising the product. A product manager job description includes defining the product vision and working closely with team members of other departments to deliver winning products.  

3 Jobs Available
Production Manager
3 Jobs Available
Merchandiser
2 Jobs Available
QA Lead

A QA Lead is in charge of the QA Team. The role of QA Lead comes with the responsibility of assessing services and products in order to determine that he or she meets the quality standards. He or she develops, implements and manages test plans. 

2 Jobs Available
Metallurgical Engineer

A metallurgical engineer is a professional who studies and produces materials that bring power to our world. He or she extracts metals from ores and rocks and transforms them into alloys, high-purity metals and other materials used in developing infrastructure, transportation and healthcare equipment. 

2 Jobs Available
Azure Administrator

An Azure Administrator is a professional responsible for implementing, monitoring, and maintaining Azure Solutions. He or she manages cloud infrastructure service instances and various cloud servers as well as sets up public and private cloud systems. 

4 Jobs Available
AWS Solution Architect

An AWS Solution Architect is someone who specializes in developing and implementing cloud computing systems. He or she has a good understanding of the various aspects of cloud computing and can confidently deploy and manage their systems. He or she troubleshoots the issues and evaluates the risk from the third party. 

4 Jobs Available
QA Manager
4 Jobs Available
Computer Programmer

Careers in computer programming primarily refer to the systematic act of writing code and moreover include wider computer science areas. The word 'programmer' or 'coder' has entered into practice with the growing number of newly self-taught tech enthusiasts. Computer programming careers involve the use of designs created by software developers and engineers and transforming them into commands that can be implemented by computers. These commands result in regular usage of social media sites, word-processing applications and browsers.

3 Jobs Available
ITSM Manager
3 Jobs Available
Product Manager

A Product Manager is a professional responsible for product planning and marketing. He or she manages the product throughout the Product Life Cycle, gathering and prioritising the product. A product manager job description includes defining the product vision and working closely with team members of other departments to deliver winning products.  

3 Jobs Available
Information Security Manager

Individuals in the information security manager career path involves in overseeing and controlling all aspects of computer security. The IT security manager job description includes planning and carrying out security measures to protect the business data and information from corruption, theft, unauthorised access, and deliberate attack 

3 Jobs Available
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