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

First ionization energy of Beryllium is 900 Kilo joules per mole and that of Boron is 801 Kj/mole. The reason is that Electronic configuration of Beryllium is 1s2 2s2, the orbitals are filled completely, its going to become stable and when an atom is stable..it is very hard to remove an electron from it and disturb its stability
While Electronic configuration of Boron is 1s2 2s1 2p1. the last p orbital is not filled completely then its going to stay unstable