Air

From AI Gemini:

What Air Is Actually Made Of

Dry air near Earth's surface is composed almost entirely of two main diatomic (two-atom) molecules, alongside a few single atoms and trace compounds:

Nitrogen ~ 78%: Two nitrogen atoms bound tightly together. This makes up the vast majority of any given sample of air.

Oxygen ~ 21%: Two oxygen atoms bound together. This is the reactive component we breathe.

Argon ~ 0.93%: A noble gas that exists as single, unbonded atoms rather than bound molecules.

Carbon Dioxide, Water Vapor, & Traces ~ 0.07%: Multi-atom molecules present in small or variable amounts depending on humidity and location.