Question

how many "d" electrons are present in Cr^+2 ion​

Answer 1

ATOMIC NUMBER OF CR OR CROMIUM = 24

NO OF ELECTRONS=24

A POSITIVE SIGN INDICATES THAT IT LOST 1 ELECTRON AND 2 MEANS IT HAS LOST TWO ELECTRONS

NOW ELECTRONIC CONFRIGURATION OF CR=[AR]4s^2 3d^4

NOW ELECTRONIC CONFRIGURATION OF CR^2=[AR]3d^4

AS CHROMIMUM WILL LOOSE ELECTRON FROM ORBITAL

THEREFORE CR^2 HAS 4 D ORIBITALS

HENCE OPTION A IS CORRECT

HOPE THAT THIS WILL HELP YOU OUT AND BEST OF LUCK FOR YOUR FUTURE AND JEE✔✔

Answer 2

Iam sorry I have mistaken the question