Question

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

Answer 1

because Be has stable Electronic configuration i.e 1s^2 2s^2 while B has configuration ---->1s^2 2s^2 2p^1 so it is easy to remove one electron from outer p orbital of Boron that's why it has low ionisation enthalpy