Which subatomic particle is responsible for the identity of an element?

• A. Proton
• B. Neutron
• C. Electron
• D. Photon

Answer: (A)

Verified step by step guidance

1. Understand that the identity of an element is determined by the number of protons in its nucleus. This number is called the atomic number (Z).
2. Recall that protons are positively charged particles found in the nucleus of an atom, and each element has a unique number of protons.
3. Neutrons, which are neutral particles in the nucleus, affect the isotope of an element but do not change the element's identity.
4. Electrons are negatively charged particles orbiting the nucleus and determine the chemical behavior of the element but not its identity.
5. Photons are particles of light and are not subatomic particles within the atom, so they do not affect the element's identity.