Considering the following statements; identify the correct statements:

(A) Scandium is regarded as a transition element, but zinc is not.
(B) $V_2O_3$ is amphoteric and $V_2O_5$ is basic oxide.
(C) The similar radii of Zr and Hf is a consequence of the lanthanoid contraction.
(D) The oxidation state of chromium in chromate and dichromate ion is same.

Choose the correct answer from the options given below.

(A), (C) and (D) only

The correct answer is Option (3) → (A), (C) and (D) only

Let’s examine each statement:

(A) Scandium is regarded as a transition element, but zinc is not.
 Correct

Transition elements are characterized by the presence of partially filled d orbitals in their atoms or ions.

• Scandium has partially filled d-orbitals in its compounds.
• Zinc has completely filled d-orbitals (d¹⁰) in both atom and common oxidation state (+2), so it is not a transition element.

(B) V₂O₃ is amphoteric and V₂O₅ is basic oxide.
 Incorrect

• V₂O₃ is basic, and V₂O₅ is acidic, not basic.

(C) The similar radii of Zr and Hf is a consequence of the lanthanoid contraction.
 Correct

Due to lanthanoid contraction, the atomic radii of elements following the lanthanoids decrease. This makes Zr and Hf have nearly identical atomic sizes.

(D) The oxidation state of chromium in chromate and dichromate ion is same.
 Correct

• In both CrO₄²⁻ and Cr₂O₇²⁻, chromium is in the +6 oxidation state.

 Correct statements: (A), (C) and (D)