Question

The softness of group $IA$ metals increases down the group because:

• A. the metallic bond strength decreases with increase in atomic size
• B. ionisation potential decreases from $Li$ to $Cs$
• C. electronegativity increases from $Li$ to $Cs$
• D. atomic size decreases from $Li$ to $Cs$

Answer 1

Answer: (A)

the metallic bond strength decreases with increase in atomic size

Alkali metals have large atomic size. The close packing of atoms is weak. Hence, they are soft. As the atomic size increases on moving down the group, the strength of the metallic bonds decreases. Hence, the softness of alkali metals increases on moving down the group.