Aviral singh
Last Activity: 5 Years ago
Answer is 2(second option)because the correct electronic configuration of Cr is:1s2 1s2, 2s2, 2 2p6 p6, 3s2, 3p6, 4s1, 3d5.
Usually we consider the electronic configuration as: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d4.
But this is wrong because 3d4 wats to achieve half stability.So it takes 1 electron from 4s2.Now 4s2 becomes 4s1 and 3d4 becomes 3d5 and attains half stability.
Now, for l=1(azimuthal quantum number)subshell is p....
And here for subshell p, number of electrons(I.e.2p6 and 3p6)total no. Of electrons=12.
For l=2(azimuthal quantum number),subshell is d....and total number of electrons for subshell d(I.e.4d5)total no. Of electrons=5....
So the combination(12,5)....i.e.option(b) is correct.
Thank you🙏
