Each atom has the same number of which two particles?

• A. Protons and neutrons
• B. Electrons and neutrons
• C. Protons and electrons
• D. Electrons and quarks

Answer: (C)

In an atom, the number of protons and electrons is always equal in a neutral atom. Protons, which are positively charged, reside in the nucleus of the atom, while electrons, which are negatively charged, orbit the nucleus. This balance between the positive charge of protons and the negative charge of electrons maintains the atom's overall neutrality.

For example, if an atom has six protons, it will also have six electrons, balancing out the charges and resulting in a stable configuration. This fundamental principle of atomic structure underlines why the equal number of protons and electrons is critical for forming neutral atoms.

The other options involve combinations that do not universally apply to all atoms. For instance, neutrons may vary in number among different isotopes of the same element, and quarks make up protons and neutrons but do not directly relate to the equality of particles within a single atom's structure.