Meaning & use
monatomic
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Meaning
adjectivenot comparablechemistry
Made up of single atoms that are not joined to one another, as in the noble gases.
Grammar: Used before a noun: a monatomic gas.
Patterns
- a monatomic gas
- a monatomic element
Helium is a monatomic gas, so each particle is one atom.
Noble gases such as neon are monatomic at room temperature.
Monatomic ions carry a charge, as in sodium ion Na+.
Common combinations
- monatomic gas
- Argon is a monatomic gas.
- monatomic ion
- Chloride is a monatomic ion.
- monatomic element
- Helium is a monatomic element.
- monatomic molecule
- A monatomic molecule contains only one atom.
Synonyms and how they differ
- single-atom
- Single-atom is a plain-language phrase for the same idea but is not the standard term in chemistry textbooks.
- atomic
- Atomic is far broader and can relate to atoms in general, so it does not specify that particles consist of one atom.
Opposites
Word family
Commonly confused: monatomic or monotonic? monatomic or diatomic?
monatomic vs monotonic
Monotonic describes something that keeps moving in one direction, and it is a mathematical term unrelated to atoms.
monatomic vs diatomic
Diatomic means two atoms joined, as in oxygen, while monatomic means single atoms.
Practice
Which of these is usually monatomic at room temperature?
Choose one answer.
Helium is a noble gas whose particles are single atoms. Oxygen, nitrogen and chlorine are diatomic.
Make it your own
Write a sentence using “monatomic”, then check it and compare it with the examples above.