Here's how to find the number of protons in a barium atom using the periodic table:

* Locate Barium: Find the element barium (Ba) on the periodic table.

* Atomic Number: The atomic number of an element is the number of protons in its nucleus. It's the large number located above the element's symbol.

* Barium's Atomic Number: Barium has an atomic number of 56.

Therefore, a barium atom has 56 protons.