Why does `He_2^+` exist whereas `He_2` does not ?

Explanation

To understand why `He_2^+` exists while `He_2` does not, we can analyze the molecular orbital (MO) theory and calculate the bond orders for both species.

### Step-by-Step Solution:

1. **Determine the Electron Configuration of Helium**:
- Helium (He) has an atomic number of 2, meaning each helium atom has 2 electrons. The electron configuration is 1s².

2. **Calculate the Total Electrons in `He_2^+`**:
...