The less stable oxidation state of `Cr` are:

Options

A. `Cr^(2+)`
B. `Cr^(3+)`
C. `Cr^(4+)`
D. `Cr^(6+)`

Explanation

To determine the less stable oxidation states of chromium (Cr), we will analyze its oxidation states and their corresponding electronic configurations.

### Step 1: Determine the Electronic Configuration of Chromium
Chromium has an atomic number of 24. Its electronic configuration is:
\[ \text{Cr: } [\text{Ar}] 3d^5 4s^1 \]

### Step 2: Identify Common Oxidation States of Chromium
Chromium can exhibit several oxidation states, including:
- +2
- +3
- +4
- +6

### Step 3: Analyze the Stability of Each Oxidation State
1. **Cr +2**:
- Electronic configuration: \( 3d^4 \)
- This state is less stable because it can easily lose an electron to reach the more stable +3 oxidation state (3d³).

2. **Cr +3**:
- Electronic configuration: \( 3d^3 \)
- This state is relatively stable due to its half-filled d subshell.

3. **Cr +4**:
- Electronic configuration: \( 3d^2 \)
- This state is also less stable because it tends to gain an electron to reach the more stable +3 oxidation state.

4. **Cr +6**:
- Electronic configuration: \( 3d^0 \)
- This state is stable as it has a noble gas configuration after losing all its d and s electrons.

### Conclusion
Based on the analysis:
- The less stable oxidation states of chromium are **+2 and +4**.

### Final Answer
The less stable oxidation states of Cr are +2 and +4.

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