Definition, Meaning & Synonyms

proton-number

noun

/ˈproʊtɒn ˈnʌmər/

Definition

The proton number is the number of protons found in the nucleus of an atom of an element, which directly determines the element’s identity.

Examples

The proton number of hydrogen is 1.
Elements are arranged in the periodic table according to their increasing proton number.
Oxygen has a proton number of 8, which means it has 8 protons in its nucleus.

Meaning

It defines the atomic identity and is equal to the number of electrons in a neutral atom. The proton number is essential in periods and groups on the periodic table.