The identity of an element is determined by the number of which subatomic particle?

• A. Protons
• B. Neutrons
• C. Electrons
• D. Quarks

Answer: (A)

Verified step by step guidance

1. Recall that the identity of an element is defined by its atomic number, which corresponds to the number of protons in the nucleus of an atom.
2. Understand that protons are positively charged subatomic particles found in the nucleus, and changing the number of protons changes the element itself.
3. Note that neutrons are neutral particles in the nucleus and can vary in number without changing the element, leading to different isotopes.
4. Recognize that electrons are negatively charged particles orbiting the nucleus and affect the atom's charge and chemical behavior but not its identity.
5. Quarks are fundamental particles that make up protons and neutrons but are not used to define the identity of an element in chemistry.