How does an atom become an ion?

An atom becomes an ion by either losing or gaining electrons, which is the fundamental basis for the formation of ions.

When an atom loses one or more electrons, it becomes positively charged and is referred to as a cation. This process can occur in various chemical reactions or when an atom interacts with its environment, such as dissolving in a solution. Conversely, when an atom gains extra electrons, it acquires a negative charge and becomes an anion. This process reflects the atom's ability to achieve a more stable electronic configuration.

In the context of the question, the option that indicates both losing and gaining electrons accurately captures this duality. It emphasizes that ions can be formed through both mechanisms, which is critical in understanding chemical reactivity, bonding, and the behavior of substances in solution, particularly in marine environments where these processes are crucial in understanding corrosion and electrochemical behavior. Thus, the correct conclusion is that either process can lead to the formation of ions, underscoring the comprehensive nature of how atoms transition to ionic states.