Name: The atomic number Z of an atom defines what element it is and is determined by how many ________ are in its nucleus.
The atomic number Z of an atom defines what element it is and is determined by how many ____ are in its nucleus.
electrons Electrons do not exist in the nucleus. While the number of electrons of a non-ionized atom may equal the number of protons (and thus be equal to atomic number Z), it does not define Z or which element the atom belongs to.
nucleons The number of nucleons in the nucleus is the mass number A; it is the sum of the atomic number N and the neutron number Z (A = N + Z).
neutrons The number of neutrons in the nucleus is called the neutron number N.