Write down electronic configuration of chromium `(Z=24)` and indicate in it.
(i) numbers of sub-shells
(ii) number of orbitals
(iii) number of electrons in M-shell

Answer

`Cr=1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^(6) 4s^(1) 3d^(5)`
(i) sub-shells `=1s, 2s, 2p, 3s, 3p, 4s` and `3d` so total subshell `=7`
(ii) orbitals `=1+1+3+1+3+1+5=15`
(iii) M-shel have `n=3` so electron `=13`