The correct order of ability to form complexes is:

Options

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

Answer

C

Explanation

Complexing tendency depends upon `"charge"//"size"` ratio.