Question

Arrange the following elements in increasing order of their atomic radii. (b) $\mathrm{Cl},\mathrm{At},\mathrm{Br},\mathrm{I}$

Answer 1

Periodic trend of atomic radius

• The atomic radius of a molecule is equal to half the distance between adjacent atoms of the same element.
• An element's atomic radius decreases across a period from left to right.
• An element's atomic radius increases from top to bottom in a group in the periodic table.

Order of atomic radii $\mathrm{Cl},\mathrm{At},\mathrm{Br}\mathrm{I}$

• Chlorine $\left(\mathrm{Cl}\right)$, Bromine $\left(\mathrm{Br}\right)$, Iodine $\left(\mathrm{I}\right)$, and Astatine $\left(\mathrm{At}\right)$ elements belong to the seventh group and atomic radii increases from top to bottom.
• The increasing order of atomic radii is as follows:

$\mathrm{CI}<\mathrm{Br}<\mathrm{I}<\mathrm{At}$