Question

What is ionization energy? how does it vary in period of the periodic table?

Answer 1

It is defined as “the amount of energy required to remove the loosely bound electron, the valence electron, of an isolated gaseous atom to form a cation”


Ionization energies increase across a Period, and decrease down a Group.


Hope it helps

Answer 2

Ionization energy increases in a period and decreases down the group

In a period as there is successive addition of electron atomic size decreases so more energy is required to remove an electron thus IE increase

In a group successive addition of shells occur so the atomic size decreases so it is easy to remove electron hence IE decreases