Question

introduction to atomic structure
fausto santos
what are atoms made of?
stated clearly
multiple - choice question
the numbers of each element, on the periodic table, are called atomic numbers.
what does the atomic number tell you about each atom?
how many neutrons they have
how many protons they have
how heavy it is
rewatch

Explanation:

The atomic number of an element is equal to the number of protons in the nucleus of an atom of that element. It does not represent the number of neutrons or the mass (how heavy it is).

Answer:

How many Protons they have