Question

what do you use to determine which element you are working with?
□ charge
□ mass #
□ # neutrons
□ atomic #
□ average atomic mass
rewatch

Explanation:

Each element has a unique atomic number, which equals the number of protons in its nucleus. Charge, mass number, neutron count, and average atomic mass can vary for isotopes or ions of the same element, so they do not uniquely identify an element.

Answer:

atomic #