Question

Electronegativity is least applicable for the element with configuration _________ .

• A. $1s^2$
• B. $1s^1$
• C. $1s^{2}2s^{2}2p^1$
• D. $1s^{2}2s^{2}2p^5$

Answer 1

The correct option is A $1s^2$

Electronegativity is the tendency of an element to attract the shared pair of electrons towards itself. So, the important requirement of applicability of electronegativity is the presence of unpaired electrons, and since, the elements with fully-filled electrons ($1s^2$) do not have a tendency to form a bond, it has the least electronegativity.