Question

On what grounds can you say that scandium $\left(\right. \text{Z} = 21 \left.\right)$ is a transition element but zinc $\left(\right. \text{Z} = 30 \left.\right)$ is not one?

• A. Incompletely filled 3d orbitals in Sc
• B. Coloured compounds
• C. Variable oxidation state
• D. None of the above

Answer 1

Answer: (A)

Scandium is one of the two elements in the first transition metal period which has only one oxidation state (zinc is the other, with an oxidation state of +2).

On the basis of incompletely filled 3d orbitals, scandium $\left(3 d^1\right)$ has incompletely filled d-orbitals $\left(\right. 3 \left(\text{d}\right)^{1} \left.\right)$ in its ground state, so it is regarded as a transition element.

On the other hand, zinc $\left(\right. \text{Z} = 30 ) \, $ has completely filled d-orbitals $\left(3 \mathrm{~d}^{10}\right)$ in its ground state.