Question

Find the magnetic moment of Fe 3+ and Fe 2+

Answer 1

heya it's Aastha...

​spin only magnetic moment = n(n+2−−−−−−√
Fe3+ Z= 26= [Ar] 3d5, 4s0
the number of unpaired electrons (n)=5 
so magnetic moment = 5(5+2)−−−−−−−√= 35−−√=5.91BM 
similarly for Fe2+  configuration is [Ar] 3d​6,4s0 
the number of unpaired electrons =4 
putting this value you can calculate the magnetic moment.
I hope it help you