proton

IPA/ˈprəʊtɒn/
KK[prˈotˌɑn]IPA/ˈprəʊtɑːn/

proton — noun

  • protonsingular
  • protonsplural

1. a positively charged particle found inside the nucleus of every atom; together w

1.nounB2
Definition

a positively charged particle found inside the nucleus of every atom; together with neutrons, it forms the core of an atom.

Example

The number of protons in an atom decides its element; hydrogen has just one.

collocation: the number of protons determines the element

Dr. Chen explained that protons carry a positive charge while electrons carry a negative one.

contrast: proton positive vs electron negative

Common collocations
  • positive charge
  • atomic nucleus
  • number of protons
  • proton beam
  • proton therapy
  • proton pump
Antonyms
  • electron

    carries a negative electric charge of equal magnitude but opposite sign

Grammar Patterns

the number of + proton

proton + noun (as modifier)

Usage Note

Frequently paired with neutron and electron when describing atomic structure. The pattern 'number of protons' is the standard way to refer to an element's atomic number. In medical contexts, proton therapy uses high-energy protons to treat certain cancers.

Common Mistakes

A proton has a negative charge.
A proton has a positive charge.
Protons are positively charged; electrons carry the negative charge.
The number of neutrons decides which element an atom is.
The number of protons decides which element an atom is.
The element is identified by its proton count (atomic number), not its neutron count.

Word family

  • protonic
    adjectiveC1
  • protonate
    verbC2
  • protonation
    nounC2

Synonym discussion

Sense: noun/1

Proton, neutron, and electron are the three fundamental particles of an atom, but they differ in charge, mass, and location. A proton carries a positive charge and sits inside the nucleus; its count defines the element. A neutron has no electric charge and also lives in the nucleus, contributing to atomic mass but not to chemical identity. An electron has a negative charge and orbits the nucleus in shells; it is far lighter than either proton or neutron. Learners often confuse which particle determines the element — that is always the proton. For example, 'Carbon has six protons, not six neutrons' and 'An atom with one proton is hydrogen, regardless of how many neutrons it has.'

proton ↗neutronelectron ↗

Common collocations

Nouns

Phrases

  • number of protons
  • proton-proton chain
  • proton gradient

Prepositions

  • in the nucleus
  • of protons

Etymology

GreekEnglish

Coined in 1920 by the physicist Ernest Rutherford from the Greek word 'prōton', meaning 'first'. Rutherford chose the name because the hydrogen nucleus — which is a single proton — is the simplest and lightest of all atomic nuclei, making it the 'first' or primary building block from which other nuclei are formed.