+An **atom** is the fundamental building block of all [matter](/wiki/matter), the smallest unit that retains the chemical identity of an [element](/wiki/element). Comprising a dense nucleus of protons and neutrons orbited by electrons, atoms are the universe's most basic constituents, forming everything we know.
+## See also
+- [Molecule](/wiki/molecule)
+- [Electron](/wiki/electron)
+- [Proton](/wiki/proton)
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