Question

Assertion (A): Metallic bond in calcium is stronger than in potassium.

Reason (R): The radii of alkaline earth metals are smaller than the corresponding alkali metals.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true, but R is not the correct explanation of A.
• C. A is true and R is false
• D. A is false and R is true.

Answer 1

The correct option is A

Both A and R are true and R is the correct explanation of A.

Explanation of the correct option:

The assertion given in the question is: Metallic bond in Calcium ($\mathrm{Ca}$) is stronger than in Potassium ($\mathrm{K}$).

The reason given is: The radii of alkaline earth metals are smaller than the corresponding alkali metals.

Both the assertion and reason are correct and the given reason is the correct explanation of the given assertion.

As Calcium belongs to alkaline earth metals and Potassium belongs to alkali metals, the Calcium will have +2 charge during metallic bonding and Potassium will have +1 charge during metallic bonding. As the charge increases the radii of the ion decreases and the delocalized gets closer to the nuclei which increases the bond.

Therefore, the correct option is (A).