The most common oxidation state exhibited by the d-block elements (and why) in the 3d series is

Options

A. `+3`, due to the participation of ns and np electrons
B. ` +3`, due to the participation of ns and (n – 1)d- electrons
C. `+2`, due to the participation of ns electrons
D. ` +2`, due to the participation of (n – 1)d unpaired electrons

Answer

To determine the most common oxidation state exhibited by the d-block elements in the 3d series, we will analyze the electronic configurations and the oxidation states of each element in this series.

### Step-by-Step Solution:

1. **Identify the Elements in the 3d Series**:
The 3d series includes the following elements: Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), and Zinc (Zn).

2. **Write the Electronic Configurations**:
- Sc: [Ar] 3d¹ 4s²
- Ti: [Ar] 3d² 4s²
- V: [Ar] 3d³ 4s²
- Cr: [Ar] 3d⁵ 4s¹ (due to stability of half-filled d subshell)
- Mn: [Ar] 3d⁵ 4s²
- Fe: [Ar] 3d⁶ 4s²
- Co: [Ar] 3d⁷ 4s²
- Ni: [Ar] 3d⁸ 4s²
- Cu: [Ar] 3d¹⁰ 4s¹ (due to stability of fully filled d subshell)
- Zn: [Ar] 3d¹⁰ 4s²

3. **Determine Possible Oxidation States**:
- **Scandium (Sc)**: +2, +3
- **Titanium (Ti)**: +2, +3, +4
- **Vanadium (V)**: +2, +3, +4, +5
- **Chromium (Cr)**: +1, +2, +3, +4, +5, +6
- **Manganese (Mn)**: +2, +3, +4, +5, +6, +7
- **Iron (Fe)**: +2, +3, +4, +5, +6
- **Cobalt (Co)**: +2, +3, +4, +5
- **Nickel (Ni)**: +2, +3
- **Copper (Cu)**: +1, +2
- **Zinc (Zn)**: +2

4. **Identify the Most Common Oxidation State**:
By analyzing the oxidation states, we can see that the +2 oxidation state is common among most of the elements:
- Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn can all exhibit a +2 oxidation state.

5. **Conclusion**:
The most common oxidation state exhibited by the d-block elements in the 3d series is **+2** due to the loss of the 4s electrons primarily, while some elements may also lose d electrons.

### Final Answer:
The most common oxidation state exhibited by the d-block elements in the 3d series is **+2** due to the participation of the ns electrons.