Which of the following options does not represent ground state electronic configuration of an atom ?

Which of the following options does not represent ground state electro

1.	Which of the following options does not represent ground state electronic configuration of an atom ?
Answer» `Is^(2) 2s^(2) 2p^(6) 3s^(2) 3P^(6) 3d^(8) 4s^(2)` `Is^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(9) 4s^(2)` `Is^(2) 2s^(2) 2p^(6) 3s^(2) 3P^(6) 3d^(10) 4s^(1)` `Is^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(5) 4s^(1)` Solution :The correct configuration should be `Is^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 3d^(10) 4s^(1)` for so, copper which has atomic number 29 (2gCu). Due to extra stability of full filled orbital of d-subshell, the last ELECTRON enter into d-orbital insted of s-orbital.