Final answer:
Positive ions have a positive charge because they have an unequal number of protons and electrons. When an atom gains or loses electrons, it becomes an ion and develops a positive or negative charge.
Step-by-step explanation:
Ions have a positive charge because they have an unequal number of protons and electrons. Atoms typically have an equal number of protons and electrons, which makes them electrically neutral. However, when an atom gains or loses electrons, it becomes an ion and develops a positive or negative charge. In the case of positive ions, also known as cations, they are formed by losing electrons.