An atom of an element that has the same number of protons but different numbers of neutrons is called a(n) *

It's called an isotope.

For example, in the element hydrogen, it has 3 stable Isotopes. These include the hydrogen atom with no neutrons, 1 neutron, and 2 neutrons. They're still an hydrogen atom, as they still have 1 proton, but they're Isotopes of hydrogen.

Each element has a different number of stable Isotopes, some may get only one, but some may get a lot.

Note that Isotopes is only the different numbers in neutrons, but not proton or electrons.

Matter- occupies space and possesses rest massno matter is the opposite

16- counting by fours