The set representing the correct order of ionic radii is

Options

A. `Na^(+) gt Li^(+) gt Mg^(2+) gt Be^(2+)`
B. `Li^(+) gt Na^(+) gt Mg^(2+) gt Be^(2+)`
C. `Mg^(2+) gt Be^(2+) gt Li^(+)gt Na^(+)`
D. `Li^(+) gt Be^(2+) gt Na^(+) gt Mg^(2+)`

Answer

A

Explanation

The ionic radii of alkali metal ions are larger than those of the corresponding alkaline earth metal ions . Also ionic radii increase down the group . Therefore , the ionic size radii decrease in the order :
`Na^(+) gt Li^(+) gt Mg^(2+) gt Be^(2+) ` i.e., option (a) is correct .