Question

Although boron (B) is smaller in size than barellium (Be). But Ist ionisation enthalpy of Barellium (Be) is higher than Boran (B) Why. Advertisement

Answer 1

In order to overcome the forces of atoms within it , even though its small in size it requires a lot of energy

Answer 2

Beryllium - $1s^{2} 2s^{2}$

Boron - $1s^{2} 2s^{2} 2p^{1}$

The ionization energy is defined as the minimum amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated neutral gaseous atom.

As Beryllium contains of a fully filled orbital $2s^{2}$ ,the s orbital can contain only 2 electrons.So the ionisation potential of Beryllium is more than the boron.

Generally partially and fully filled orbitals have more stabilization energy though they are of small size.