What is the no of unpaired electrons and sum of spin of Gd

Dear student, The electronic configuration of Gd = [Xe]6s²,4f⁷,5d^{1 So, we see 7 electrons in 4f and 1 in 5d orbitals are unpaired. Total number of unpaired electrons-8} The configuration clearly suggest that all the electrons except 4f and 5d are paired,so the sum of spin quantum number values for these electrons will be 0(as values will be + 1/2and -1/2 for the paired e-s).Now for 7 electrons in 4f and 1 e- in 5d i.e total of 8e-s,the sum of spin quantum no. value will be 8/2 = 4 (as these e-s are not paired so value of spin quantun no. taken as +1/2 thereby comprising of total 8/2 = 4). Now total sum will be = 4 + 0 = 4 Thank you.