write the electronic configuration of chromium and predict its number of subshells, number of electrons in subshell having l=0, number of electrons having n+l value=3, number of electrons in the highest value of n.

The electron configuration for chromium is 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{4}.

However, in the case of chromium there is one empty d sub orbital, one of the electrons from the 4s orbital will move up to the 3d orbital and make the the actual electron configuration 1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{5}.

Therefore,

**Predicted electron configurations:** Cr ( *Z* = 24): [Ar] 4 s^{2}3d^{4}

**Actual electron configurations:** Cr ( *Z* = 24): [Ar] 4 s^{1}3d^{5}

(From the above table, we get,)

**Predict its number of subshells**

**Ans:** Chromium has 10 subshells viz - 1s, 2s, 2p, 3s, 3p, 3d, 4s, 4p, 4d, 4f

**Number of electrons in subshell having l=0**

**Ans:** There are 4 subshells and the first three sub shells (n=1, n=2 and n=3) has 2 electrons each and (n=4) has 1 electron.

**Number of electrons having n + ℓ value=3**

**Ans:** Total 8 electrons has n + ℓ value=3.

**Number of electrons in highest value of n**

**Ans:** Highest value is the last orbital (N orbital); n=4 i.e, 1 electron.