Question

The transition metals are characterized at:

• A. completely filled $d$ subshells
• B. completely filled $f$ subshells
• C. partially filled $d$ subshells
• D. partially filled $f$ subshells
• E. both $\left(A\right)$ and $\left(C\right)$ are correct

Answer 1

Answer: (C)

partially filled $d$ subshells

According to the IUPAC definition of transition metals an element whose atom has a partially filled $d$ subshell or which can give rise to cations with an incomplete $d$ subshell.

The correct option is partially filled $d$ subshell.