How many d electrons are there on the Fe metal atom in Li₃[Fe(OH)₆]? A)1 B)3 C)5 D)6

Question

Quizplus · Accepted Answer

To determine the number of d electrons on the Fe metal atom, we need to look at the electron configuration of Fe. Fe is a transition metal and has the electron configuration [Ar] 3d6 4s2. In the given complex, Fe is complexed with six water molecules and one hydroxide ion, which together form an octahedral complex around the Fe atom. Since water and hydroxide ions are weak field ligands, they do not significantly split the d orbital energy levels of the Fe atom. Therefore, the d orbital degeneracy is not lifted and all the five d orbitals are available for electron pairing. Hence, Fe would have 5 d electrons in this complex. 
Therefore, the correct answer is (C) 5.

How Many D Electrons Are There on the Fe Metal