MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The d-block elements are distributed into four transition series based on the filling of d-orbitals: First transition series (3d series): Sc (Z=21) to Zn (Z=30) Second transition series (4d series): Y (Z=39) to Cd (Z=48) Third transition series (5d series): La (Z=57), Hf (Z=72) to Hg (Z=80) Fourth transition series (6d series): Ac (Z=89), Rf (Z=104) to Cn (Z=112) Therefore, there are a total of 4 transition series of d-block elements. Answer: 4