The atomic number of an element is the number of protons in the nucleus of an atom of that element.

Here's what it tells you:

* Identifies the element: Every element has a unique atomic number. For example, all carbon atoms have 6 protons (atomic number 6), while all oxygen atoms have 8 protons (atomic number 8).

* Determines the chemical properties: The number of protons in an atom's nucleus determines its positive charge, which in turn dictates how the atom will interact with other atoms, forming chemical bonds.

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