Concept:An atom that gains or loses electrons becomes a charged particle called an ion.
Explanation:Atoms are electrically neutral because they have equal numbers of protons and electrons.
When an atom loses an electron, it has more protons than electrons, so it becomes positively charged.
When an atom gains an electron, it has more electrons than protons, so it becomes negatively charged.
This charged atom, whether positive or negative, is known as an ion.
Therefore, the correct option is B.
Answer:B. An ion