Water Distribution Grade 1 Certification Practice Exam

What is the general definition of an ion?

1. Atom

2. Molecule

3. Electron

4. Compound

The correct answer is: Atom

An ion is best defined as an atom that has gained or lost one or more electrons, resulting in a net electrical charge. This definition aligns closely with the concept of an atom because an ion is essentially a charged atom. When an atom loses electrons, it becomes a positively charged ion (cation), while gaining electrons results in a negatively charged ion (anion). A molecule, on the other hand, refers to a group of two or more atoms bonded together, which may include both charged ions and neutral atoms. An electron is a subatomic particle that carries a negative charge, but it is not itself an ion; instead, electrons are what can be lost or gained during the process of ionization. A compound is a substance formed when two or more different elements bond together, which can include molecules or ions, but is not synonymous with the concept of an ion. Thus, the relationship between an ion and an atom is fundamental, making the definition of an ion as an atom with a charge the most accurate choice.