In the context of ions, how does an atom become an ion?

• A. By gaining or losing one or more electrons, resulting in a net electric charge
• B. By gaining or losing protons, changing its atomic number without changing charge
• C. By gaining or losing neutrons, changing its mass number and becoming charged
• D. By forming a chemical bond that always keeps the total number of electrons unchanged on the atom

Answer: (A)

Verified step by step guidance

1. Understand that an atom is electrically neutral when it has an equal number of protons (positively charged) and electrons (negatively charged).
2. Recognize that ions are atoms or molecules that have a net electric charge due to an imbalance between the number of protons and electrons.
3. Know that the number of protons in an atom's nucleus defines the element and does not change during ion formation; protons are not gained or lost in this process.
4. Realize that an atom becomes an ion by either gaining electrons (resulting in a negatively charged ion, called an anion) or losing electrons (resulting in a positively charged ion, called a cation).
5. Understand that changes in neutrons affect the mass number but do not cause the atom to become charged, and forming chemical bonds involves sharing or transferring electrons but does not necessarily change the net charge of the individual atom.