Question

How do atoms exist?

Answer 1

Atoms are building blocks of all matter. They are the smallest particles of elements that can take part in a chemical reaction. Atoms generally exist as molecules of elements and molecules of compounds. Example(molecules of elements) oxygen molecule is formed by the combination of two oxygen atoms. Another example is water molecule$H_{2}O$(molecules of compounds) which has two hydrogens and one oxygen atom

The atoms of noble gases (eg. He, Ne, etc.) are unreactive and exist in the free state (as a single atom). But atoms of many elements are very reactive and usually exist either in the form of molecules or ions.