Question

What is meant by ionization energy?

Answer 1

Ionization energy

• “It represents the amount of energy required to remove an electron from the valence shell of an isolated gaseous atom (X) in its ground state.”
• The ionization energy is expressed in units${\text{kJ mol}}^{-1}$.
• Ongoing left to right in a period, generally, the ionization energy increases.
• On going down the group, generally, the ionization energy decreases.