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Chemistry vocabulary · Atoms and the Periodic Table

Atom

Meaning in chemistry, with examples

/ˈætəm/nounCore term

In chemistry, atom means: The smallest unit of an element that keeps its chemical identity. It has a tiny nucleus of protons and neutrons, with electrons moving around it.

In Turkish: atom

How it is used

Used from the very first lesson. You count atoms when you balance equations, talk about the atoms of an element, and describe what an atom gains, loses or shares in a reaction.

Example sentences

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

  2. Count the atoms on each side before you say the equation is balanced.

Common collocations

  • carbon atom
  • hydrogen atom
  • atoms of an element
  • central atom
  • atomic structure
  • elementA pure substance made of only one kind of atom, all with the same number of protons. It cannot be broken down into simpler substances by chemical reactions.
  • electronA tiny particle with a negative charge that moves around the nucleus of an atom. Chemical bonds and reactions are mostly about how these particles are shared or transferred.
  • atomic numberThe number of protons in the nucleus of an atom. It identifies the element: every carbon atom has 6 protons and every oxygen atom has 8.
  • isotopeOne of two or more forms of the same element whose atoms have the same number of protons but a different number of neutrons, such as carbon-12 and carbon-14.
  • moleculeA group of two or more atoms held together by covalent bonds. It is the smallest particle of a substance such as water or oxygen gas that still has that substance's chemical properties.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Atoms and the Periodic Table

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