Trick for Slater's Rule, calculation of screening constant and effective nuclear charge.

In this video I explained the trick for Slater's Rule, calculations of screening constant and effective nuclear charge.
Correction :for Titanium
Ti (z=22) Electronic configuration is 1s2 2s2 2p6 3s2 3p6 3d2 4s2. If we want to calculate the screening constant for one d electron in 3d..(There will be no effect of 4s electrons in screening) Trick is : for electrons in nth shell (screening constant is 0.35) and for electrons in n-1, n-2,n-3 etc (screening constant is 1). Number of electrons in nth shell (3d +3p+3s)=10. Do minus 1. Because we are calculating sigma for that. So 9×0.35 =3.15 and number of electrons in n-1 and n-2 shells (2p+2s+1s)=10. So 10×1=10. Total screening constant is 3.15 +10 = 13.15. Effective nuclear charge = atomic number - screening constant
= 22-13.15 = 8.85.
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