The set representing the correct order of ionic radius is

Options

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

Answer

D

Explanation

Lesser is the positive charge higher is the radius Moreover the size increases down the group Therefore
`N^(o+) gt Li^(o+) gt Mg^(2+) gt Be^(2+)`
3rd period 2nd period 3rd period 2nd period Hence `Na^(o+) = 102` pm
` Li = 76` pm
`Mg^(2+) = 72` pm
`Be^(2+) =31` pm .