Question

Identify the correct statement (s) among the following:

• A. The electronegativity of an element is the tendency of an isolated atom to atttract an electon
• B. The second ionization potential of boron is greater than carbon
• C. Nitrogen has postive electron gain enthalpy eventhough it is an electronegative element
• D. The first electron affinity of fluorine is greater than that of chlorine

Answer 1

Answer: (B), (C)

Nitrogen has postive electron gain enthalpy eventhough it is an electronegative element

(a)The tendency of an atom in a molecule to attract the shared pair of electrons towards itself is known as electronegativity of that atom.

(b) Electronic configuration of $B^{+}=1s^{2}2s^2$
Electronic configuration of $C^{+}=1s^{2}2s^{2}2p^1$
As $B^{+}$ has fully filled stable elctronic configuration, hence, ionization potential of $B^{+}$ will be higher than $C^{+}$
$\therefore$ The second ionization potential of boron is greater than carbon.

(c) As Nitrogen has stable electronic configuration i.e. $1s^{2}2s^{2}2p^3$, gaining an electron will destabilize it. Hence, nitrogen has positive electron gain enthalpy.

(d) As a general trend, down the group electron affinity decreases but due to small size of flourine, interelectronic repulsion is more in flourine whereas chlorine can accommodate the incoming electrons easily. Hence, the first electron affinity of chlorine is greater than that of flourine.