Question

Arrange the following as per the instruction given in the brackets.
(iv) Na, K, Li (Increasing atomic size).

Answer 1

Atomic size:-

• Atomic size basically refers to the radius of the atom.
• It increases down the group. Across a period the atomic radius first decreases and then increases.
• As we go down the group the number of shells increases, hence the distance between the nucleus and electrons also increases.
• Due to this the atomic radius increases. Therefore the correct order of increasing atomic size is- $\mathrm{Li}<\mathrm{Na}<\mathrm{K}$.