Question

The maximum no. of electrons present in shell is given by the formula 2n²and the maximum no. of electrons filled in M shell is 18. But in the element calcium we only fill 8 electrons in the M shell and move on to the N shell. why?

Answer 1

According to Bohr burry rule, the number of electron exceeds 8 when it gives 2 electrons to next level shell. In Calcium, the number of electron cannot exceed more than 8 in M shell until it gives 2 electrons to next level. Therefore the electronic configuration of calcium is

₂₀Ca : 2 8 8 2