What will be the bond order of the species with electronic configuration `1s^(2) 2s^(2) 2p^(5)`?

Options

A. One
B. Two
C. Three
D. Zero

Explanation

To determine the bond order of the species with the electronic configuration `1s² 2s² 2p⁵`, we will follow these steps:

### Step 1: Identify the Total Number of Electrons
The given electronic configuration is `1s² 2s² 2p⁵`. We can count the total number of electrons:
- From `1s²`: 2 electrons
- From `2s²`: 2 electrons
- From `2p⁵`: 5 electrons

**Total electrons = 2 + 2 + 5 = 9 electrons.**

### Step 2: Determine the Molecular Orbitals
Next, we need to fill the molecular orbitals based on the total number of electrons. The order of filling for molecular orbitals is as follows:
1. σ(1s)
2. σ*(1s)
3. σ(2s)
4. σ*(2s)
5. σ(2p_z)
6. π(2p_x) = π(2p_y)
7. π*(2p_x) = π*(2p_y)
8. σ*(2p_z)

### Step 3: Fill the Molecular Orbitals
Now, we will fill the molecular orbitals with the 9 electrons:
1. σ(1s) can hold 2 electrons (filled)
2. σ*(1s) can hold 2 electrons (filled)
3. σ(2s) can hold 2 electrons (filled)
4. σ*(2s) can hold 2 electrons (filled)
5. σ(2p_z) can hold 2 electrons (filled)
6. π(2p_x) can hold 2 electrons (filled)
7. π(2p_y) can hold 2 electrons (filled)

At this point, we have filled:
- 2 (σ(1s)) + 2 (σ*(1s)) + 2 (σ(2s)) + 2 (σ*(2s)) + 2 (σ(2p_z)) + 2 (π(2p_x)) + 1 (π(2p_y)) = 9 electrons.

### Step 4: Count Bonding and Antibonding Electrons
Now, we will count the number of electrons in bonding and antibonding molecular orbitals:
- **Bonding Molecular Orbitals:**
- σ(1s): 2 electrons
- σ(2s): 2 electrons
- σ(2p_z): 2 electrons
- π(2p_x): 2 electrons
- π(2p_y): 1 electron (only partially filled)

**Total bonding electrons = 2 + 2 + 2 + 2 + 1 = 9 electrons.**

- **Antibonding Molecular Orbitals:**
- σ*(1s): 2 electrons
- σ*(2s): 2 electrons
- π*(2p_x): 0 electrons
- π*(2p_y): 0 electrons
- σ*(2p_z): 0 electrons

**Total antibonding electrons = 2 + 2 = 4 electrons.**

### Step 5: Calculate Bond Order
Now, we can calculate the bond order using the formula:
\[ \text{Bond Order} = \frac{(\text{Number of bonding electrons} - \text{Number of antibonding electrons})}{2} \]

Substituting the values:
\[ \text{Bond Order} = \frac{(9 - 4)}{2} = \frac{5}{2} = 2.5 \]

### Final Answer
The bond order of the species with the electronic configuration `1s² 2s² 2p⁵` is **2.5**.

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