What is the shape (molecule geometry) of formaldehyde (CH₂O)?

Formaldehyde (CH₂O) has a trigonal planar molecular geometry. Here's how we determine this:

1. First, we need to understand the Lewis structure of formaldehyde. The central atom is Carbon, which is bonded to two Hydrogen atoms and one Oxygen atom.

2. The Carbon atom forms two single bonds with the two Hydrogen atoms and a double bond with the Oxygen atom.

3. The double bond with Oxygen is considered as one electron group. Therefore, Carbon has three electron groups in total.

4. According to the VSEPR (Valence Shell Electron Pair Repulsion) theory, a molecule with three electron groups around the central atom will have a trigonal planar shape.

5. Therefore, formaldehyde (CH₂O) has a trigonal planar molecular geometry.