atom

Meanings

1. 1nouncountablechemistryphysics

   The tiny basic unit of a chemical element, made of a nucleus with electrons moving around it.

   Grammar: Countable: one atom, many atoms.

   Patterns

   • an atom of something

   A water molecule contains two hydrogen atoms and one oxygen atom.

   Scientists once believed the atom could not be split.

   Gold is made of gold atoms packed closely together.

2. 2nouncountablefigurative

   An extremely small amount of something.

   Grammar: Usually appears in negative phrases such as not an atom of.

   Patterns

   • not an atom of something

   There was not an atom of truth in the rumor.

   She showed no atom of fear as she climbed onto the stage.

   He had not an atom of energy left after the marathon.

Word forms

Common combinations

split the atom

Researchers first managed to split the atom in the 1930s.

hydrogen atom

A hydrogen atom is the simplest of all.

atom bomb

The atom bomb changed the course of the war.

nucleus of an atom

The nucleus of an atom holds protons and neutrons.

charged atom

A charged atom is called an ion.

Synonyms and how they differ

particle

Particle is a broader word for any tiny piece of matter, including parts smaller than an atom.

speck

Speck means a tiny visible spot, while atom in this sense stresses a minimal amount of a quality.

iota

Iota is the closer synonym for the figurative sense, and it is mostly used in negative sentences.

Word family

atomic adjective

relating to atoms or nuclear energy

atomize verb

to break into very small particles or spray as a fine mist

subatomic adjective

smaller than an atom

diatomic adjective

made of two atoms

Commonly confused: atom or molecule? atom or Adam?

Practice

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