The first ionisation potential of `Na,Mg,Al` and `Si` are in the order

Options

A. Na lt Mg gt Al lt Si
B. Na gt Mg gt Al gt Si
C. Na lt Mg lt Al gt Si
D. Na gt Mg gt Al lt Si

Answer

A

Explanation

`Na = 1s^2 , 2s^2 2p^6, 3s^1 to` (Easy to release `e^(-)`)
`Mg = [Ne] 3s^2 to` (Half filled orbital)
`Al = [Ne] 3s^2 3p^1 to ` (Can have tendency to donate `e^(-)`)
`Si = [Ne] 3s^2 3p^2`
Hence I.E `Si gt Al lt Mg gt Na`.