Question

Calculate the effective nuclear charge at the periphery of nitrogen atom when an extre electron is added in the formation of anion . Also calculate the effective nuclear charge of N-atom.

Answer 1

Ground state electron configuration of N(Z=7)=`1s^(2)2s^(2)2p^(3)`
Electron configuration of `N^(-)=(1s^(2))(2s^(2)2p^(4))`
Shielding constant for the last 2p electron,
`sigma=[(2xx0.85)+(5xx0.35)]=3.45`
So `Z_(eff)=Z-sigma=7-3.45=3.55`
Electron configuration of `N^(+)=(1s^(2))(2s^(2)2p^(2))`
Shielding constant for the last 2p electron,
`sigma=[(2xx0.85)+(3xx0.35)]=2.75`
So `Z_(eff)` for the last electron on `N^(+)=7-2.75=4.25`