Question

write the electronic configuration of a) Cr b) Mn+2.​

Answer 1

Answer:

Correct Electron Configuration for Chromium (Cr)

Half-filled and fully filled subshell have got extra stability. Therefore, one of the 4s2 electrons jumps to the 3d5 so that it is half-filled (see video below). This give us the (correct) configuration of:

1s2 2s2 2p6 3s2 3p6 3d5 4s1

For the Cr2+ ion we remove one electron from 4s1 and one from the 3d5 leaving us with:

1s2 2s2 2p6 3s2 3p6 3d6 3d4

For the Cr3+ ion we remove a total of three electrons (one from the 4s1 and two from the 3d5) leaving us with

1s2 2s2 2p6 3s2 3p6 3d6 3d3

Mn has Atomic number = 25 ,

So electronic configuration ofMn+2 will be

[Ar]3d5 4s0

Electron Config of the ion Mn2+ as

1s2 2s2 2p6 3s2 3p6 3d6 4s2 3d9 3d3