Question

Which of the following is a member of first transition series?

• A. Ni
• B. Ac
• C. Cd
• D. Au

Hint:

First transition series = \(3d\) elements (Sc to Zn). Remember: Zn and Cd (with \(d^{10}\)) are not typical transition metals.

Answer 1

The Correct Option is A

Step 1: Define the first transition series.
The first transition series comprises the \(3d\) elements from Sc (21) to Zn (30).
Step 2: Classify options.
Ni (28) lies in the \(3d\) block \(\Rightarrow\) first transition series.
Ac (89) is an actinide; Au (79) belongs to the \(5d\) series; Cd (48) has a \(d^{10}\) configuration in its common oxidation state and is not considered a transition element.
Step 3: Conclusion.
Hence, Ni is the correct choice.