Methane formula.

**The reasoning** Methane is the simplest **hydrocarbon** — a compound made of only carbon (C) and hydrogen (H). The name itself gives you a clue: "meth-" means one carbon atom, and "-ane" tells you it's a saturated hydrocarbon (all single bonds). Carbon has 4 valence electrons and needs 4 more to be stable. Each hydrogen has 1 electron and needs 1 more. So one carbon atom bonds with **four hydrogen atoms**: CH₄. This tetrahedral molecule is what we burn in cooking gas! **Why the wrong options tempt you** - **CO₂** is carbon dioxide — what you breathe out. It has carbon, but paired with oxygen, not hydrogen. - **H₂O** is water — hydrogen is there, but with oxygen instead of carbon. - **NH₃** is ammonia — contains hydrogen, but the central atom is nitrogen, not carbon. All these contain hydrogen or carbon, so they might look familiar if you're rushing! **Quick takeaway** Remember: **Meth = 1 carbon, -ane = hydrocarbon, so methane = CH₄** — one carbon holding hands with four hydrogens, like cooking gas in your kitchen.