What is equal to the number of protons in an atom?

Each atom contains an equal number of protons and electrons; these particles will be equal in value to an element's atomic number. For example, the element gold, or AU, has an atomic number of 79, meaning it has 79 protons and 79 electrons. Atomic number is not to be confused with atomic mass.

Protons and electrons are just two of the three subatomic particles that make up an atom. The third is the neutron, and this particle is the odd one out in terms of number. While protons and electrons will number equal to an element's atomic number, an atom's total number of neutrons is equal to the rounded atomic mass minus the atomic number.