Four diatomic species are listed in different sequence .Which of these represent the correct order of their increasing bond order?

Options

A. `C_(2)^(2-) lt He_(2)^(+) lt NO lt O_(2)^(-)`
B. `He_(2)^(+) lt O_(2)^(-) lt NO lt C_(2)^(2-)`
C. `O_(2)^(-) lt NO lt C_(2)^(2-) lt HE_(2)^(+)`
D. `NO lt C_(2)^(2-) lt O_(2)^(-) lt He_(2)^(+)`

Explanation

To determine the correct order of increasing bond order for the given diatomic species (C2²⁻, He2⁺, NO, and O2⁻), we will calculate the bond order for each species step by step.

### Step 1: Calculate the bond order for C2²⁻
1. **Electronic Configuration**:
- C2²⁻ has 10 electrons:
- σ1s², σ*1s², σ2s², σ*2s², π2px², π2py², σ2pz²
2. **Bonding and Antibonding Electrons**:
- Bonding electrons: 2 (σ1s) + 2 (σ2s) + 2 (π2px) + 2 (π2py) + 2 (σ2pz) = 10
- Antibonding electrons: 2 (σ*1s) + 2 (σ*2s) = 4
3. **Bond Order Calculation**:
- Bond Order = 1/2 (Number of bonding electrons - Number of antibonding electrons)
- Bond Order = 1/2 (10 - 4) = 3

### Step 2: Calculate the bond order for He2⁺
1. **Electronic Configuration**:
- He2⁺ has 1 electron:
- σ1s², σ*1s¹
2. **Bonding and Antibonding Electrons**:
- Bonding electrons: 2 (σ1s) = 2
- Antibonding electrons: 1 (σ*1s) = 1
3. **Bond Order Calculation**:
- Bond Order = 1/2 (2 - 1) = 0.5

### Step 3: Calculate the bond order for NO
1. **Electronic Configuration**:
- NO has 11 electrons:
- σ1s², σ*1s², σ2s², σ*2s², π2px², π2py², σ2pz², π*2px¹
2. **Bonding and Antibonding Electrons**:
- Bonding electrons: 2 (σ1s) + 2 (σ2s) + 2 (π2px) + 2 (π2py) + 2 (σ2pz) = 10
- Antibonding electrons: 2 (σ*1s) + 2 (σ*2s) + 1 (π*2px) = 5
3. **Bond Order Calculation**:
- Bond Order = 1/2 (10 - 5) = 2.5

### Step 4: Calculate the bond order for O2⁻
1. **Electronic Configuration**:
- O2⁻ has 18 electrons:
- σ1s², σ*1s², σ2s², σ*2s², σ2pz², π2px², π2py², π*2px², π*2py¹
2. **Bonding and Antibonding Electrons**:
- Bonding electrons: 2 (σ1s) + 2 (σ2s) + 2 (σ2pz) + 2 (π2px) + 2 (π2py) = 10
- Antibonding electrons: 2 (σ*1s) + 2 (σ*2s) + 2 (π*2px) + 1 (π*2py) = 7
3. **Bond Order Calculation**:
- Bond Order = 1/2 (10 - 7) = 1.5

### Summary of Bond Orders
- C2²⁻: Bond Order = 3
- He2⁺: Bond Order = 0.5
- NO: Bond Order = 2.5
- O2⁻: Bond Order = 1.5

### Step 5: Order of Increasing Bond Order
Now, we can arrange the bond orders in increasing order:
1. He2⁺ (0.5)
2. O2⁻ (1.5)
3. NO (2.5)
4. C2²⁻ (3)

### Final Answer
The correct order of increasing bond order is:
**He2⁺ < O2⁻ < NO < C2²⁻**