Both helium and beryllium have ns^(2) valence electronic configuration. However, beryllium forms compounds and helium cannot form compounds. Explain.

Both helium and beryllium have ns^(2) valence electronic configuration

1.	Both helium and beryllium have ns^(2) valence electronic configuration. However, beryllium forms compounds and helium cannot form compounds. Explain.
Answer» Solution :Both HELIUM and beryllium have `ns^(2)` valence electronic configuration. Beryllium has an electron PAIR in 2S orbital and all three 2p orbitals are vacant. The paired electron of 2s orbital can be excited to 2p orbital thereby giving a covalency of 2. Helium has an electron pair in '1s' orbital and there is no SCOPE for excitation of electrons in first SHELL. Hence, Helium can not form any compounds.