Highest covalent character is found in which of the following?

The charge/size ratio of a cation determines its polarizing power. Which of the following sequences represents the increasing order of the polarizing power of the cations $K^+$,$Ca^{2+}$,$Mg^{2+}$,and $Be^{2+}$?

Choose the correct statement regarding Fajan's rule.

To a mixture of $LiCl$,$AlCl_3$ and $NaCl$,ether is added. Which of these will be extracted into ether?

Which of the following compounds will have the least ionic character?

Which of the following orders are correct regarding their covalent character?
$i. KF < KI$
$ii. LiF < KF$
$iii. SnCl_2 < SnCl_4$
$iv. NaCl < CuCl$
The correct option is