Final answer:
The iron(II) ion has a +2 charge and has lost two electrons, while the iron(III) ion has a +3 charge and has lost three electrons, affecting the chemistry and properties of compounds they form.
Step-by-step explanation:
The iron(II) ion, often referred to as Fe²⁺, is a form of iron that has lost two electrons and thus exhibits a +2 charge. Conversely, the iron(III) ion, designated as Fe³⁺, is the form of iron that has lost three electrons, carrying a +3 charge. This difference in electron loss and subsequent charge is significant as it determines the chemistry, including the type of compounds they can form and the color of the solutions or compounds they are part of.
In the Stock system for naming, these ions are represented by roman numerals in parentheses to indicate the positive charge; for example, Fe²⁺ is called the iron(II) ion, while Fe³⁺ is called the iron(III) ion.