1. Understand What the Atomic Number Represents:

* The atomic number is the number of protons in an atom's nucleus. It's a fundamental identifier for an element.

2. Look it Up on the Periodic Table:

* The periodic table is organized by atomic number. Find oxygen (symbol: O) on the table.

* The atomic number will be located above the element's symbol.

3. The Answer:

* You'll find that oxygen's atomic number is 8. This means an oxygen atom has 8 protons in its nucleus.

Important Note: While the number of protons defines an element, the number of neutrons can vary within an element, creating isotopes. However, the atomic number always stays the same for a specific element.