Question

Which of the following element belongs to the second transition series of the periodic table?

• A. Ni
• B. Au
• C. La
• D. Nb

Answer 1

The correct option is D Nb

The second transition series or 4d series corresponding to the filling of 4d sublevel consists of the following 10 elements of the $5^{th}$ period: Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag and Cd. Hence Nb belongs to second transition series.