Question

Explain the following:

(i) Atomic radius of sodium is greater than that of lithium.

Answer 1

Step-1: Introduction

Atomic radii are the distance of the electrons in the outermost from the atomic nucleus.

Step-2: Trend in the periodic table

It increases from top to bottom in a group and decreases from left to right in a period but is highest for a noble gas.

Step-3: Reason

Sodium ($\mathrm{Na}$) and Lithium ($\mathrm{Li}$) belong to group 1. Sodium has higher atomic radii than Lithium. In Sodium, the outermost shell is M-shell (n=3) but in lithium, the outermost shell is L-shell (n=2). Thus , the increase in number of shells increase the size of the atom in a group.

Step-4: Final answer

Therefore, atomic radius of Sodium is greater than that of Lithium.