Question

An element with configuration $1 s^{2}, 2 s^{2} 2 p^{6}, 3 s^{2} 3 p^{5}$ will form a compound of highest ionic character with the element having configuration

• A. $1 s^{2} 2 s^{2} 2 p^{6}$
• B. $[A r] 4 s^{3} \cdot 3 d^{10}$
• C. $[ Ar ] 4 s^{1}$
• D. $1 s^{2}, 2 s^{1}$

Answer 1

Answer: (C)

$[ Ar ] 4 s^{1}$

Answer 2

The electronic configuration of chlorine is $1 s^2 2,2 s^{2} 2 p^{6}, 3 s^{2}, 3 p^{5}$ It is a halogen. It will formal a compound of highest ionic character with alkali metals of ${ }^{\circ}$ size.
In all of the given electronic configurations, [Ar] $4 s^{1}$
(i.e., potassium) is the configuration of an alkali metal of comparable size.