Question

Calculate the effective nuclear charge of 4s electron in potassium

Answer 1

The effective nuclear charge of 4s electron of potassium is 2.20

The formula for the effective nuclear charge is

  Z* =Z−σ

where Z*=effective nuclear charge

           Z=no. of protons

           σ=Shielding Constant

The electronic configuration of K is 1s2,2s2,2s2,2p6,3s2,3p6,4s1 , and this atom has 4 shells in it. Therefore

σ=0.85×number of electrons in(n−1)thshell+1.00×total number of electronsin the inner shell

           σ=0.85×8+1.00×10

           σ=16.80

         Z* =Z−σ

              =19−16.80

              =2.20

therefore the Z* experience by 4s electron of Potassium  is 2.20