The size of the following species increases in the order

Options

A. `Mg^(2+) lt Na^(+) lt F^(-) lt A1`
B. `F^(-) lt A1 lt Na^(+) lt Mg^(2+)`
C. `A1 lt Mg ^(2+) lt F^(-) lg Na^(+)`
D. `Na^(+) , lt A1 lt F^(-) lt Mg^(2+)`

Answer

A

Explanation

`Mg^(2+) , Na^(+) ` and `F^(-)` are isoelectronic ions (having two filled shells ) therefore their size increae in the order `: Mg^(2+) , lt Na^(+) lt Na^(2+) lt F^(-)` All belongs to the 3rd period and also does not carry any charge Therefore it has the largest size . Thus the overall sizes increases in the order `: Mg^(2+) lt Na^(2+) lt F^(-) lt A1`