The following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statement gives the correct picture:

Options

A. The chemical reactivity decreases in alkali metals but increases in halogens with increase in atomic number
B. In alkali metals, the reactivity increases but in halogens it decreases with increase in atomic number down the group.
C. In both alkali metals and halogens, the chemical reactivity decreases with increase in atomic number down the group.
D. The chemical reactivity increases with increase inatomic number down the group in both alkali metals and halogens.

Answer

B

Explanation

In alkali metals, the reactivity increases on moving down the group due to decrease in the value of ionization enthalpy while in halogens, the reactivity decreases on moving down the group due to decrease in the value of reduction potential.