The atomic number of an atom is the key characteristic that defines the identity of an element.
The atomic number is the characteristic that provides the most information about what kind of element an atom is. This number represents the number of protons in the nucleus of an atom, defining its identity.
For example, any atom with six protons is the element carbon, regardless of its neutrons or electrons. The atomic number also indicates the number of electrons in an atom and distinguishes one element from another.
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