Define the term 'bond order' and find bond order of `O_(2)`.

Explanation

### Step-by-Step Solution

**Step 1: Define Bond Order**
Bond order is defined as the half of the difference between the number of electrons in bonding molecular orbitals and the number of electrons in anti-bonding molecular orbitals. Mathematically, it can be expressed as:
\[ \text{Bond Order} = \frac{1}{2} (N_b - N_a) \]
where \( N_b \) is the number of electrons in bonding orbitals and \( N_a \) is the number of electrons in anti-bonding orbitals.

**Step 2: Determine the Molecular Orbital Configuration of \( O_2 \)**
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