How Many Elements are There

Introduction

Everything that has mass and occupies space is matter. Everything that we sense using the five senses matter. Humans have always tried to understand it at the most basic level. We try to find out what the fundamental building block of matter is. Democratic, a Greek philosopher, believed that matter consisted of tiny, indivisible particles and called them ‘Atomos.’ meaning ‘undivided’ in Greek. The modern understanding is that ‘atoms’ are the smallest indivisible part of matter. Although further study of the inside of atoms is being done, it remains a different topic to discuss given the higher level of technical knowledge required. Now, the tiny particles making up matter can be individual atoms or groups of connected atoms known as ‘molecules.’ This takes us to the subject of our discussion-What is an element? An element is a substance whose constituents are atoms of the same kind, as opposed to a compound of the same groups of connected atoms. An example of an element would be helium, of the same type, whereas water has a group of atoms containing two hydrogens and one oxygen atom, represented as. To sum up, ‘The smallest indivisible building block of an element is an atom, and that of a compound is a molecule.’

How many elements are there?

• The modern periodic table is a regular arrangement of all known elements based on trends and properties shown by them.

• The table was an improvisation of a similar one previously developed by Mendeleev.

• The elements are carefully placed in the table's ‘groups’ and ‘periods’ based on their similarities with other elements of the same group or period.

• The table has 18 groups and 7 periods containing 4 blocks of elements showing collective properties. According to the table, the total number of elements discovered is 118.

• The upper limit on the number of elements is largely due to the nuclear stability of an atom.

• Larger nuclei may not be stable in normal conditions; hence, naturally occurring elements are around 98, including those present in trace amounts and those produced as byproducts of nuclear fission processes.

• The atomic numbers of the naturally occurring elements range from 1 through 92.

• The elements can either be found as pure substances or in a compounded form linked to other chemical species.

• In this case, obtaining pure elements requires further chemical and physical separation methods.

• Elements are not always obtained in pure form, as some impurities or compounds may always be present with them.

• Thirty-two elements out of the naturally occurring ones are obtained in their pure forms.

• Scientists are discovering more elements in nuclear decay processes and accelerator projects, but their instability makes it difficult to control or study them.

• Science grows daily, and studying and developing more elements may be possible with more technologies.

Properties of elements

• The atoms consist of electrons revolving around their nucleus, which has protons and neutrons in it. The atomic number is the number of protons present in an atom. There are equal numbers of protons and electrons in an atom.

• Number of Protons = Atomic Number

• Number of Electrons = Atomic Number

• Number of Neutrons = Mass Number - Atomic Number, where the Mass Number equals the total number of protons and neutrons.

• The elements can be classified into three main categories: metals, nonmetals, and metalloids.

• These are arranged so that each row (period) and the group have their own properties, known as periodic and group properties.

• For instance, each period tells you about the number of energy levels of that atom like row 3 elements will have 3 energy levels.

• Each group element has the same valence electron. Like these, there are many more properties and characteristics as per the groups and periods.

Current Elements

• The present table consists of 118 elements in total. These elements have been discovered and included in the table over the years. The table was last updated in 2016 with four elements, namely Nihonium (113), Moskovia (115), Tennessine (117), and Oganesson (118).

• The primary 98 elements within the periodic table are naturally occurring elements, whereas the remaining can be artificially synthesised in nuclear labs.Only 32 of the 98 elements are pure; the remainder exist as compounds. 10 elements are found in trace amounts out of 98, which are technetium (Z = 43), promethium (Z = 61), astatine (Z = 85), francium (Z = 87), neptunium ( Z= 93), plutonium (Z = 94), americium (Z =95), curium (Z = 96), berkelium (Z =97), and californium (Z = 98).

• Eight elements out of the twelve natural elements are stable and not subject to decay.

• The elements having atomic numbers greater than 82, such as lead, are unstable and can be decayed. Only a few naturally existing elements are found in their native state.

• These include noble gases and elements like gold, copper, and silver.

Rare elements vs Native elements

Rare elements are those that are artificially made through nuclear reactions through the radioactive decay of some common elements. The number of elements in the periodic table is made up of these decay reactions of unknown elements that have been in existence for a long time where native elements are present in their natural form in an uncombined state. Very few native elements are found in compound form.

The future of the periodic table

The last six elements were found from 2012 to 2016, giving us the remaining elements at the

bottom of the periodic table. Chemical properties are known to be changed continuously, thus

giving us discoveries of the elements. Most of the changes in the table will come from synthesised elements, which will be unstable compared to natural elements, thus quickly

decaying. So, there is always a chance of discoveries in the atomic field.

Notes

• There are a total of 30 elements in the p-block. P-block elements have their last electrons in their p subshell.

• The sixth period in the modern periodic table has 14 extra elements that are

• placed at the bottom of the periodic table, separately, known as “f-block” elements.

• Transition elements are found in groups number 3-12 in the modern periodic

table, i.e., d-block.

• Elements are distinguished by their atomic number. It is the number of protons present in the nucleus of the atom that makes up the element. The atoms of the hydrogen element have a single proton at the centre, and no other type of atom can have such a unique configuration.

• The electrons in an atom revolve around the nucleus. The number of electrons in an atom is equal to that of the protons in the nucleus. Interestingly, this number also depends on the number of neutrons present. The stability of the nucleus is related to both numbers. An unstable nucleus cannot form a stable atom. Hence, nuclear stability is important for atoms.