Question

How do the following properties vary in periodic table?

(iv) Ionization enthalpy

Answer 1

Ionization enthalpy

Ionization enthalpy or ionization energy is the amount of energy required for the removal of an electron from an isolated gaseous atom.

Trends in the periodic table

1. Down the group:- Due to the addition of shells, the atomic radius increases. Hence the distance between the electrons and nucleus is far apart. Therefore ionization energy decreases when we go down the group.
2. Across a period:- As the atomic radius decreases the ionization energy increases from left to right across the period.
3. Noble gases:- Noble gases have the highest ionization enthalpies.

Thus, down the group ionization energy decreases, across the period ionization energy increases. Noble gases have the highest ionization energy.