Question

Calculate the EN of silicon using Allred-Rochow equation if the covalent radius of silicon is $1.175\stackrel{o}{A}$.

Answer 1

Allred-Rochow equation is:
$\chi =0.359\times \frac{Z_{eff}}{r^2}+0.744$
$(Z_{eff}$ is calculated on the basis of Slater's rule taking all the electrons)

Electronic configuration of Si (Z=14) is $1s^{2}2s^{2}2p^{6}3s^{2}3p^2$

$Z_{eff}=14-(0.35\times 4+0.85\times 8+2\times 1)=3.80$

$\chi =0.359\times \frac{3.80}{(1.175{)}^2}+0.744=1.73$