The atomic number of an element is equal to the number of:
- A. Neutrons in the nucleus
- B. Protons in the nucleus
- C. Protons and neutrons combined
- D. Electron shells
Explanation
The atomic number equals the number of protons in the nucleus and determines the identity of the element. The mass number is the sum of protons and neutrons; isotopes of an element share an atomic number but differ in mass number.