Chlorine (Cl) has an atomic number of 17, which means it has 17 protons in its nucleus. The number of protons in an atom determines its atomic number and defines the element. In a neutral atom, the number of protons is balanced by the same number of electrons orbiting the nucleus. Since chlorine has 17 protons, it has 17 electrons in its neutral state.

When chlorine gains or loses electrons, its charge changes. When it gains one electron, it becomes a negatively charged chloride ion (Cl-) with an overall charge of -1. This occurs because the addition of an electron increases the number of negatively charged particles (electrons) by one, resulting in a net negative charge. Conversely, when chlorine loses one electron, it becomes a positively charged chlorine cation (Cl+) with an overall charge of +1. This happens because the removal of an electron decreases the number of negatively charged particles by one, leading to a net positive charge.

The charge of chlorine depends on its electronic configuration and the number of electrons it has gained or lost compared to its neutral state.