Question

Which element in period $2$ has the greatest tendency to gain electrons?

Answer 1

Electronegativity is the tendency of an atom in a molecule to attract the shared pair of electrons towards itself. The electronegativity property describes the tendency of atoms in various elements to attract bond-forming electron pairs.

Complete answer:
As we move from left to right across a period in the periodic table, the tendency to gain electrons increases. On moving from left to right across a period in the periodic table, there is an increase in the nuclear charge of the elements. At the same time, the size of the elements decreases. As a result, the effective nuclear charge acting on the valence electrons increases. Hence, the tendency to gain electrons increases.
Fluorine has the greatest tendency to attract a shared pair of electrons and therefore it is known as the most electronegative element. Fluorine is the most electronegative element on the periodic table. Its electronegativity value is $3.98$ . Caesium is the least electronegative element. Its electronegativity value is $0.79$ . Electro positivity is the exact opposite of electronegativity; therefore, we can say that Caesium is the most electropositive element.

Note:
We know that electronegativity decreases as one moves down the periodic table's groups due to the inert pair effect. For example, the group of electronegativity of the halogen is as follows $F > Cl > Br > I$ . The most electronegative elements are those that require only a few electrons to complete their valence shells and have the smallest inner electron shells between the positive nucleus and the valence electrons.