Question

Define the term ‘Electronegativity’ and state its unit.

Answer 1

Hint: We know that the elements are arranged in a systematic order in the periodic table. The elements are arranged primarily in the increasing order of their atomic radius. However, as the atomic radius and the number of electrons increases in the orbitals, several other properties of the atoms change. Electronegativity of an element is one more such critical feature of an atom.

Complete Step by Step answer
We know that every atom consists of subatomic particles called the protons (that carry a positive charge), neutrons (that has a negative charge), and electrons (that has negative charge). There is an equilibrium that is maintained in every atom so as to stay neutral.
But however, there is always an instability among atoms that results in them forming molecules with the same atoms or with other different atoms to form a stable molecule or compound. So, we can clearly see that there is a tendency of these atoms to attract another pair of electrons from another atom. This tendency results in the formation of molecules and ions. The measure of this tendency of atoms to attract electrons towards itself is called electronegativity.
There are a number of factors that define the electronegativity of an atom. The atomic radius of an atom, which is the distance of the valence electrons from the nucleus of an atom has a strong effect on the electronegativity of the atom. The more is the atomic radius of an atom; the more is its associated electronegativity.
Although there are various methods to find the electronegativity of an atom, the most commonly used method is the Pauling’s scale. However, electronegativity is a dimensionless quantity for it only describes the tendency of an atom to attract electrons towards itself.

Note
On the periodic table the most electronegative element is Fluorine (with an electronegativity of $ 3.98 $ ) and the least electronegative element is Caesium (with an electronegativity of $ 0.79 $ ). Although electronegativity is a dimensionless quantity it is conventional to specify that it was calculated using Pauling’s scale by adding a suffix ‘Pauling units’ along with the electronegativity calculated.