atom
noun (countable)
UK/ˈæt.əm/US/ˈæt.əm/
A very small amount or part of something.
Example Sentences
He didn't care an atom about what others thought of him.
There wasn't an atom of truth in his statement.
She didn't spare an atom of effort in preparing for the competition.
The room was spotless; not an atom of dust was visible.
He ignored an atom of criticism and continued with his work.
They searched the area but found not an atom of evidence.
Despite the challenges, she maintained not an atom of doubt in her abilities.
He didn't reveal an atom of information about the confidential project.
Thesaurus
Synonyms
How to Use
The smallest unit of a chemical element, retaining its identity in chemical reactions.An “atom” is the basic building block of ordinary matter. Each atom consists of a central nucleus (made of protons and neutrons) surrounded by electrons moving in regions of space called orbitals. The number of protons (atomic number) defines which chemical element the atom represents—hydrogen, helium, carbon, and so forth. Protons carry a positive charge, electrons are negative, and neutrons are neutral; together, their interactions and arrangements govern the atom’s stability and chemical behavior.When atoms bond, they form molecules or compounds, creating the variety of substances we see around us. In everyday contexts, references to “atomic” level phenomena often involve discussion of energy release (like nuclear fission or fusion) or advanced imaging (like scanning electron microscopy). But on a simple level, each type of atom is uniquely identified by its proton count, which gives rise to all the diversity of matter in the universe.
Alternatives
Synonyms or near-synonyms are rarely needed for “atom,” given its precise scientific meaning. “Particle” is broader and can include other small entities (electrons, neutrinos, etc.). “Molecule” is larger, referring to bonded atoms. “Ion” references a charged atom or group of atoms. Terms like “subatomic particle” apply to the protons, neutrons, and electrons themselves, but not to the atom as a whole unit. So “atom” remains the best term for describing the smallest component of an element retaining chemical properties.
Writing
In scientific or academic writing, clarify which aspect of the atom you’re focusing on—electronic structure, nuclear composition, isotopes, or chemical bonding. For instance, “The hydrogen atom contains one proton in its nucleus and one electron in its orbital.” If explaining nuclear physics, outline differences between stable and unstable isotopes. In chemistry papers, highlight how atoms join to form molecules, referencing valence electrons or atomic orbitals. When discussing periodic trends, note that atomic size, ionization energy, or electronegativity depends on atomic structure. Thoroughly citing established theories—like quantum mechanics or Rutherford’s gold-foil experiment—reinforces how our understanding of the atom developed historically.
Casual Conversation
In everyday conversation, “atom” might show up metaphorically—“I don’t have an atom of doubt”—implying not the slightest bit. Or you might see it in pop culture references to nuclear power (“splitting the atom”) or in idiomatic expressions like “breaking things down to the atomic level.” Teachers might quickly define an atom for students as “the tiny piece of matter that forms elements,” while science documentaries or museum exhibits spotlight atomic structure to explain how matter is built. Discussions about new technologies—like quantum computing or nuclear reactors—often mention atoms in passing, signifying the fundamental scale at which these innovations operate. Although most people don’t deal directly with atoms in everyday life, the concept underpins a huge swath of modern science. Chatting about “atoms” often fosters awe at how small building blocks can shape enormous realities, from DNA’s complex instructions to star formation’s nuclear reactions.
Etymology
“Atom” traces back to the Greek “atomos,” meaning “uncuttable” or “indivisible.” Early philosophers like Democritus theorized that matter could be subdivided only so far before reaching a fundamental, indivisible particle—an “atomos.” Over millennia, scientific investigations evolved from this philosophical speculation to modern atomic theory. By the 19th century, John Dalton’s work confirmed that elements contain unique atoms, culminating in the later discovery of subatomic particles—protons, neutrons, electrons—revealing atoms weren’t truly “indivisible” after all. Despite that, “atom” still stands for the smallest chemical unit preserving an element’s identity, grounding our comprehension of matter’s structure.
