Which of the following is a true statement regarding the atomic number of an element?

• A. It is equal to the number of protons in the nucleus of an atom.
• B. It is equal to the number of protons and neutrons in the nucleus of an atom.
• C. It is equal to the number of electrons in the nucleus of an atom.
• D. It is equal to the number of electrons and neutrons in the nucleus of an atom.

Answer: (A)