When atoms gain or lose electrons, they become negatively or positively charged. They are known as:

• A. Molecules
• B. Isotopes.
• C. Ions.
• D. Radioactive.
• E. Unstable atoms.

Answer: (C)

Verified step by step guidance

1. Begin by understanding the concept of ions. Ions are atoms or molecules that have gained or lost one or more electrons, resulting in a net electrical charge.
2. Consider the process of electron transfer. When an atom loses electrons, it becomes positively charged, known as a cation. Conversely, when an atom gains electrons, it becomes negatively charged, known as an anion.
3. Differentiate between ions and other atomic forms. Molecules are groups of atoms bonded together, isotopes are variants of elements with different neutron numbers, and radioactive atoms are unstable due to excess energy or particles.
4. Recognize that ions are distinct from isotopes, molecules, and radioactive atoms because their defining characteristic is the gain or loss of electrons, leading to a charge.
5. Conclude that the correct term for atoms that have gained or lost electrons, resulting in a charge, is 'ions'.