Question

The electronic configuration of few elements is given below. Mark the statement which is not correct about these elements.
(i) $1s^{2}2s^{2}2p^{6}3s^1$
(ii) $1s^{2}2s^{2}2p^5$
(iii) $1s^{2}2s^{2}2p^6$
(iv) $1s^{2}2s^{2}2p^3$

• A. (i) is an alkali metal.
• B. (iii) is a noble metal.
• C. (i) and (ii) form ionic compounds.
• D. (iv) has high ionisation enthalpy.

Answer 1

The correct option is B (iii) is a noble metal.

(i) is an alkali metal. It readily loses an electron to attain a noble gas configuration.

(iii) is a noble gas. It has completed its octet.

Highly electropositive (i) and highly electronegative (ii) form ionic compounds.

(iv) has high ionization enthalpy as removal of an electron will break half-filled 2p subshell.