Question

The electronic configurations of three elements, $A,B$ and $C$ are given below.

$A:1s^{2}2s^{2}2p^6$

$B:1s^{2}2s^{2}2p^{6}3s^{2}3p^3$

$C:1s^{2}2s^{2}2p^{6}3s^{2}3p^5$

Stable form of $A$ may be represented by the formula:

• A. $A_3$
• B. $A_2$
• C. $A_4$
• D. $A$

Answer 1

The correct option is D $A$

Element	Electronic configuration
$A\left(Ne\right)$	$1s^{2}2s^{2}2p^6$

Outermost shell of "$A$" is full.

So, it is a noble gas.

Its atomic number is $10$ i.e., it is neon.

Since $"A"$ is a noble gas, its atoms do not react with each other and remain stable as monoatomic $‘A^{\prime }$ only.

Hence correct answer is option $\left(A\right).$