Write electronic configuration of `Fe^(2+)` and `Fe^(3+)` ions. Which of these has more number of unpaired electrons? Atomic no. of `Fe` is `26`.

Answer

Fe atom has `26` electrons. `Fe^(2+)` and `Fe^(3+)` ions are formed by removal of two and three electrons respectively from Fe atom and hence contain `24` and `23` electrons respectively. Their electronic configuration are:
`(##RES_PHY_CHM_V01_XI_C02_E01_024_A01##)`
`Fe^(2+)` has `4` unpaired electrons while `Fe^(3+)` has `5` unpaired electrons. Therefore, `Fe^(3+)` has more number of unpaired electrons.