Chemistry / Unit 1 Chem 0050 short lesson, about 20 seconds
Molecule
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The idea
A molecule is two or more atoms joined by chemical bonds, moving as a single unit.
In practice
A water molecule is a fixed unit of two hydrogen atoms bonded to one oxygen atom, never three loose atoms in liquid water.
Where people slip
A molecule can be identical atoms, like paired oxygen atoms, or different atoms, like water — a single element can qualify too.
Your place on the trail
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