The ionization energy of boron is less than that of beryllium because : — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Write the ground state electronic configurations: Beryllium (Be) is 1s^2 2s^2, and Boron (B) is 1s^2 2s^2 2p^1. Step 2: In beryllium, the electron is removed from a 2s orbital, which is closer to the nucleus and has greater penetration power than the 2p orbital from which boron's electron is removed. Step 3: Because the 2p electron of boron is shielded more and is less tightly bound by the nucleus, it requires less energy to remove than beryllium's 2s electron.