d-block elements have tendency for complex formation because of

Options

A. Small size of metal ions
B. High ionic charges
C. Availability of vacant d-orbitals
D. All of these

Answer

**Step-by-Step Solution:**

1. **Understanding D-Block Elements**:
- D-block elements are also known as transition metals and are located in groups 3 to 12 of the periodic table. They consist of 38 elements.

2. **Electronic Configuration**:
- The electronic configuration of the first d-block element, Scandium (Sc), is given as [Ar] 3d¹ 4s². This indicates that it has one electron in the 3d subshell and two in the 4s subshell.

3. **Vacant D Orbitals**:
- Transition metals have vacant d orbitals. The presence of these vacant d orbitals is crucial as they can accommodate electrons from other atoms or ions, facilitating bond formation.

4. **Factors Contributing to Complex Formation**:
- **Vacant D Orbitals**: The availability of these orbitals allows transition metals to form coordinate bonds with ligands (molecules or ions that can donate electron pairs).
- **High Ionic Charges**: Transition metals can exhibit multiple oxidation states, leading to high ionic charges. This property enhances their ability to attract and bond with ligands.
- **Small Size of Metal Ions**: The relatively small size of transition metal ions allows them to have a higher charge density, which increases their ability to form complexes.

5. **Evaluating the Options**:
- Option A: Small size of metal ions – Correct.
- Option B: High ionic charges – Correct.
- Option C: Availability of vacant d orbitals – Correct.
- Therefore, the correct answer is **Option D: All of these**.

**Final Answer**: D-block elements have a tendency for complex formation because of all of the following: small size of metal ions, high ionic charges, and availability of vacant d-orbitals.

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