IGCSE Chemistry Practice Exam 2026 – Complete Study Resource

The molecular formula of methane is indeed CH4. This formula indicates that one molecule of methane is composed of one carbon atom (C) and four hydrogen atoms (H). Methane is the simplest alkane and a significant component of natural gas, which is used as a fuel.

In molecular formulas, the subscripts next to each element represent the quantity of that atom in a single molecule of the compound. In the case of CH4, the presence of one carbon atom and four hydrogen atoms is characteristic of methane's structure, which is tetrahedral. This arrangement allows for the complete bonding of the carbon atom to the four hydrogen atoms, resulting in a stable and saturated hydrocarbon.

Other options represent different compounds. For instance, C2H4 refers to ethylene, which consists of two carbon atoms and four hydrogen atoms, and C3H8 is propane, with three carbon atoms and eight hydrogen atoms. H2 is diatomic hydrogen, representing a molecule of hydrogen gas composed of two hydrogen atoms and no carbon. Each of these alternatives has distinct properties and structures that differentiate them from methane.