Apart from tetrahedral geometry, another possible geometry for `CH_(4)` is square planar with the four `H` atoms at the corners of the square and the `C` atom at its centre. Explain why `CH_(4)` is not square planar?

Explanation

To explain why `CH₄` (methane) is not square planar, we can break down the reasoning into two main points:

### Step 1: Understanding the Tetrahedral Geometry
1. **VSEPR Theory**: According to the Valence Shell Electron Pair Repulsion (VSEPR) theory, the shape of a molecule is determined by the repulsion between electron pairs around the central atom. In the case of `CH₄`, the carbon atom is surrounded by four hydrogen atoms.
2. **Tetrahedral Structure**: The four hydrogen atoms are arranged in a tetrahedral geometry to minimize the repulsion between the bonding pairs of electrons. This arrangement leads to bond angles of approximately 109.5 degrees.