`A1^(3+)` ion has a lower ionic radius than `Mg^(2+)` ion because

Options

A. Mg atom has less number of neutrons than Al
B. `A1^(3+)` has a higher nuclear charge than `Mg^(2+)`
C. Their electronegativities are different
D. A1 has a lower ionisation potential than Mg atom

Answer

B

Explanation

`AI^(3+) = 10e^(-) = 13p` nuclear charge
`Mg^(2+) = 10e^(-) = 12p` nuclear charge
Nuclear charge `prop (1)/(lonic radius)`
Hence, `Al^(3+)` has higher nuclear charge than `Mg^(2+)`