This character is a Other Symbol and is commonly used, that is, in no specific script. The character is also known as nuclear installation (on maps).
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. The word that U+269B forms with similar adjacent characters prevents a line break inside it.
The CLDR project calls this character “atom symbol” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: atheist, atom, symbol.
This character is designated as an emoji. It will be rendered as monochrome character on conforming platforms. To enable colorful emoji display, you can combine it with Variation Selector-16: ⚛️ See the Emojipedia for more details on this character’s emoji properties.
The Wikipedia has the following information about this codepoint:
The Rutherford model was devised by Ernest Rutherford to describe an atom. Rutherford directed the Geiger–Marsden experiment in 1909, which suggested, upon Rutherford's 1911 analysis, that J. J. Thomson's plum pudding model of the atom was incorrect. Rutherford's new model for the atom, based on the experimental results, contained new features of a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and with this central volume containing most of the atom's mass; this region would be known as the atomic nucleus. The Rutherford model was subsequently superseded by the Bohr model.