Pair of ions with polarising power

Which ion has a higher polarising power ?

Write the name of alkali metal with polarising power close to that of magnesium.

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

Which of the following ion has maximum polarising power

Which of the following ion has maximum polarising power

Which out of Na^(+) and Mg^(+) ion, has greater polarising power and why?