Which term describes a positively charged ion that has lost electrons?

A positively charged ion that has lost electrons is specifically referred to as a cation. When an atom loses one or more electrons, it has more protons than electrons, resulting in an overall positive charge. This process typically occurs during chemical reactions where atoms seek to achieve a more stable electron configuration.

Cations play an essential role in ionic compounds, where they combine with negatively charged ions (anions) to form stable structures. Understanding the formation of cations is crucial in recognizing how elements interact and bond in various chemical contexts, such as in salinity and electrochemical applications.

The other terms provided do not accurately describe a positively charged ion. Anions refer to negatively charged ions, isoelectronic ions have the same number of electrons but may differ in their charge or elemental identity, and isotopic ions pertain to atoms of the same element with different numbers of neutrons, which does not relate to charge. Therefore, the term cation is the correct descriptor for positively charged ions.