Which of the following best describes what an ion could be?

• A. An atom or molecule that has gained or lost electrons and carries a net charge
• B. A neutral atom with an equal number of protons and electrons
• C. A substance that cannot be broken down into simpler substances by chemical means
• D. A molecule formed by covalent bonding between two nonmetals

Answer: (A)

Verified step by step guidance

1. Understand the definition of an ion: An ion is a species that carries a net electrical charge due to the loss or gain of electrons.
2. Recall that a neutral atom has an equal number of protons (positive charges) and electrons (negative charges), resulting in no net charge.
3. Recognize that a substance that cannot be broken down into simpler substances by chemical means is an element, not necessarily an ion.
4. Know that a molecule formed by covalent bonding between two nonmetals is a neutral molecule, not an ion.
5. Conclude that the best description of an ion is 'An atom or molecule that has gained or lost electrons and carries a net charge.'