Question

Calculate effective nuclear charge that added electron would experience in F-atom in the formation of negative ion. (Round-off to the nearest integer)

Answer 1

The expression for the effective nuclear charge $Z_{eff}$ is

$Z_{eff}=Z-\sigma$

Here, Z is the nuclear charge and $\sigma$ is the shielding constant.

For fluoride ion, $Z=9$ and $\sigma =0.85\times 2+0.35\times 7=4.15$

Hence, $Z^{\ast }=Z-\sigma =9-4.15=4.85$

Hence, the effective nuclear charge that added electron would experience in F-atom in the formation of negative ion is 4.85. So, the nearest integer is 5.