From effective nuclear charge, I learned that the bond pair on flourine and chlorine is the same with +7. However, why is that so? Don't we calculate them from Coulomb's Law using F=kQ1Q2/r^2 ? Or is it because of the presence of the other electron shells that Causes the F to be Attraction (kQ1Q2/r^2 )- Repulsion (kQ1Q3/r^2 )? So as a whole we can just take Zeff=Z-S?
Also, how does having more electrons 'screen' the pull by the +7 nucleus? The only reason why I think the pull will be less for chlorine is that r is smaller (assuming we solved the first question and the charge experienced is actually +7).
Thanks for the help chemicalforums