i have a doubt in electronic configuration of atom.in the electronic configuration of calcium it is =2,8,8,2.as in the m shell the maximum no of electrons that can be accomadated will be 18 electrons.so why the electronic configuration cannot be for calcium as =2,8,10

Asked by my3shyll | 2nd Jan, 2016, 11:13: AM

Expert Answer:

Calcium with atomic number as 20 have its electronic configuration as 2,8,8,2 and not as 2,8,10 because the energy of 4s orbital is less than 3d orbital, so 4s orbital is filled first.

Therefore, the electronic configuration of calcium is 1s2 2s2 2p6 3s23p6 4s(2,8,8,2) but not as 1s2 2s2 2p6 3s2 3p6 3d2(2,8,10)


Answered by Vaibhav Chavan | 3rd Jan, 2016, 12:13: PM