Question

Assertion (A): The valency of sodium and chlorine atom is the same. ​

Reason (R): Sodium loses 1 electron while chlorine gains 1 electron to complete their octet.

• A. (A) is true, but (R) is false. ​
• B. (A) is false, but (R) is true.​
• C. Both (A) and (R) are true, but (R) is not a correct explanation of (A).​
• D. Both (A) and (R) are true, and (R) is correct explanation of (A).​

Answer 1

The correct option is D Both (A) and (R) are true, and (R) is correct explanation of (A).​

The electronic configuration of sodium is 2, 8, 1.
The electronic configuration of chlorine is 2, 8,7.
So in order to attain nearest noble gas electronic configuration, sodium will lose 1 electron and chlorine gains 1 electron.
Therefore, valency of sodium and chlorine is 1.