The charge/size ratio of a cation determines its polarizing power. Which one of the following sequences represents the increasing order of the polarizing power of the cationic species, `K^(+), Ca^(2+), Mg^(2+), Ba^(2+)`?

Options

A. `Ca^(2+) lt Mg^(2+) lt Be^(2+) lt K^(+)`
B. `Mg^(2+) lt Be^(2+) lt K^(+) lt Ca^(2+)`
C. `Be^(2+) lt K^(+) lt Ca^(2+) lt Mg^(2+)`
D. `K^(+) lt Ca^(2+) lt Mg ^(2+) lt Be^(2+)`

Answer

D

Explanation

The polarizing power increases when charge/size
ratio of cation increases which in turn increases
as the charge increases and size decreases , i.e.,
`K^(+) lt Ca^(2+) lt Mg^(2+) lt Be^(2+)` .