monatomic

[ mon-uh-tom-ik ]

adjective

, Chemistry.

1. having one atom in the molecule.
2. containing one replaceable atom or group.
3. having a valence of one.

monatomic

/ ˌmɒnəˈtɒmɪk; ˌmɒnəʊəˈtɒmɪk /

adjective

1. (of an element) having or consisting of single atoms

   argon is a monatomic gas

2. (of a compound or molecule) having only one atom or group that can be replaced in a chemical reaction
3. a less common word for monovalent

Other Words From

• mona·tomi·cal·ly adverb

Word History and Origins

Origin of monatomic¹

First recorded in 1840–50; mon- + atomic

Example Sentences

Moreover, in a paper published in April, Hemley and his colleagues report signs that hydrogen squeezed up to 360 GPa holds on to its diatomic character and fails to morph into a monatomic metal.

From Nature

Its ratio of specific heats has very nearly the ideal value 1.666, appropriate to a monatomic molecule.

From Project Gutenberg

The same value had previously been found for mercury vapour by Kundt and Warburg, and had been regarded as confirmatory of the monatomic character attributed on chemical grounds to the mercury molecule.

From Project Gutenberg

The molecule of iodine, for example, is monatomic at 1200� C., but becomes diatomic at the ordinary temperature.

From Project Gutenberg

The supporters of the formula Hg2Cl2 pointed out that dissociation into mercury and mercuric chloride would give this value, since mercury is a monatomic element.

From Project Gutenberg