Question

Why are Na+ and K+ unable to form covalent bonds?

Short answer

By losing the single electron in the 3s orbital (in the case of Na) or the 4s orbital (in the case of K), Na⁺ and K⁺ gain an outer shell of eight electrons, resulting in Na⁺ and K⁺.

They'd have to reclaim electrons in these orbitals to form a covalent bond, sacrificing the stability that comes with an outer shell of eight electrons and no additional electrons.

Step-by-step solution

Definition of Covalent bond-

A covalent bond is defined as a bond established by the equal sharing of electrons between the linked atoms, which indicates that both atoms participating in the bond creation will get an electron. Between the nonmetals, a covalent connection is established.

Why can't Na+ and K+ form covalent bonds-

Both Na⁺ and K⁺ are metals that belong to the periodic table's group IA.

Na+ has an electronic configuration of 1s² 2s² 2p⁶

K+ has an electronic configuration of 1s² 2s² 2p⁶3s² 3p⁶.

Both ions (Na⁺ and K⁺) met the octet rule in this case.

They must gain an electron in these orbitals in order to make a covalent bond, which will destabilise the orbital with an outer shell of eight electrons and no further electrons.

As a result, the Na⁺ and K⁺ can't form covalent bonds.