Question
Which transition series includes elements Co and Mo respectively?
MHT CET
Chemistry
d and f Block Elements
2026
MHT CET 2026 (11 April Shift 2)
MHT CET Chemistry Question (2026) — Solution
Options
- A. 4d and 5d
- B. 5d and 6d
- C. 3d and 4d
- D. 3d and 6d
Answer
C. 3d and 4d
Step-by-step solution
Cobalt (Co) has the atomic number 27 and its electronic configuration is [ Ar ] 3d^ 7 4s^ 2 . It belongs to the first transition series, which is the 3d series. Molybdenum (Mo) has the atomic number 42 and its electronic configuration is [ Kr ] 4d^ 5 5s^ 1 . It belongs to the second transition series, which is the 4d series. Therefore, Co and Mo belong to the 3d and 4d transition series respectively. Answer: 3d and 4d
Related: Chemistry — d and f Block Elements · All PYQ Banks