Atoms of the same element that have different numbers of neutrons

• A. Isotopes
• B. Ions
• C. Isomers
• D. Electrons

Answer: (A)

Atoms of the same element with different numbers of neutrons are isotopes. Protons determine the identity of the element, so those atoms share the same element and the same chemical behavior, but the neutrons add to the mass, making the total mass number different. This can affect nuclear stability and radioactive properties, while the chemistry remains largely similar because electron arrangements don’t depend on the neutron count. For example, carbon-12 and carbon-14 both have six protons, but carbon-14 has two extra neutrons and is radioactive. In contrast, an ion would involve a different number of electrons and carries a charge, an isomer refers to different structural arrangements of atoms, and electrons are the subatomic particles orbiting the nucleus.