Chemistry / Unit 2 Chem 0264 short lesson, about 20 seconds
Diatomic Elements
Captions available
The idea
Seven elements exist naturally as two-atom molecules rather than single atoms: hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine.
In practice
A sample of pure oxygen gas is made of O2 molecules, never lone oxygen atoms drifting separately in the container.
Where people slip
These seven are memorized as a fixed list, not derived from a rule — no simple pattern on the periodic table predicts them.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
- Nothing yet depends on this.
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