With the help of molecular orbital theory, predict which of the following species is diamagnetic
` Li_(2)^(+) ,O_2 ,O_(2)^(+) , O_(2)^(2-)`

Explanation

To determine which of the given species is diamagnetic using molecular orbital theory, we will analyze each species one by one. The species are: \( \text{Li}_2^+, \text{O}_2, \text{O}_2^+, \text{O}_2^{2-} \).

### Step 1: Calculate the total number of electrons for each species.

1. **For \( \text{Li}_2^+ \)**:
- Each lithium atom has 3 electrons. Therefore, for 2 lithium atoms, the total is \( 2 \times 3 = 6 \) electrons.
- Since it has a +1 charge, we subtract 1 electron: \( 6 - 1 = 5 \) electrons.

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