Following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statements gives the correct picture: A)In alkali metals the reactivity increases but in the halogens it decreases with increase in atomic number down the group B)The reactivity decreases in the alkali metals but increases in the halogens with increases in atomic number down the group. C)In both the alkali metals and the halogen the chemical reactivity decreases with increases in atomic number down the group D)Chemical reactivity increases with increases in atomic number down the group in both the alkali metals and halogens.

Options

A. Least ionisation enthalpy on the left and highest negative electron gain enthalpy on the right.
B. Non-merallic character on the left and metallic character on the right.
C. High atomic radii on the left and small atomic radii on the right.
D. Highest electronegativity on the left and least electronegativity on the right.

Answer

A

Explanation

Elements on the left side have lowest ionisation enthalpy due to which they can very esily lose electrons while the elements on the right can accept electrons easily as they show highest negative electron gain enthalpy.