Molecule
MOL-i-kyool
/ˈmɒlɪkjuːl/
A group of two or more atoms held together by chemical bonds.
Molecules can range from simple (like H2O) to extremely complex (like DNA or proteins), but they always involve discrete atoms bonded together.
The story behind the word. The word 'molecule' comes from the French 'molécule,' which was derived from the New Latin 'molecula.' This in turn is a diminutive of the Latin word 'moles,' meaning 'mass' or 'bulk.' So, a molecule literally means 'a small mass.' The term gained prominence in the 19th century as scientists began to understand how atoms combine to form larger, distinct units.
Word relationships
- compound: A compound is a substance formed from two or more elements chemically bonded; a molecule is the smallest unit of a compound (or element, if diatomic).
- particle: More general term; a molecule is a specific type of particle.
Commonly confused with
- Atom: An atom is a single unit of an element; a molecule is a group of two or more atoms bonded together.
Word family
- molecular (adjective): Relating to or consisting of molecules.
Collocations
- water molecule
- organic molecule
- large molecule
- gas molecules
Example sentences
- "A single water molecule consists of two hydrogen atoms bonded to one oxygen atom." Explaining the composition of water.
- "DNA is a giant molecule that carries genetic instructions." Referring to complex biological structures.
- "In a gas, molecules move freely and are far apart from each other." Describing the state of matter.
Memory hook
Think of a 'MOLE-cule' as a 'MOLE' (animal) that has 'CULES' (cuddles) with other atoms, forming a group. MOLE-cule: atoms that 'cuddle'
When not to use
Do not use 'molecule' interchangeably with 'atom'; a molecule is a collection of atoms.
Fun facts
- The smallest molecule is diatomic hydrogen (H2), consisting of just two hydrogen atoms.
- The concept of molecules helped explain the laws of definite and multiple proportions in chemistry.
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