Question

Which of the following is least likely to form bonds? helium hydrogen nitrogen oxygen

Answer 1

Answer: Helium is least likely to form bonds.

Explanation:

Helium has the electronic configuration $1s^{2}$. As the 1s sub-shell is completely filled so there is no need for helium to form bonds with other atoms.

Whereas, nitrogen has the electronic configuration $1s^{2} 2s^{2} 2p^{3}$. As the p sub-shell is half filled, it has the tendency to accept more electrons. Therefore, nitrogen is more susceptible to form bonds as compared to helium.

Thus, it is concluded that helium is least likely to form bonds.

Answer 2

Helium as it's a nobel gas and therefore does not need to form any bonds to get a full shell of outer electrons (as its shell is already full) making it stable.