* Chlorine atom (Cl): This is the neutral form of chlorine, containing 17 protons and 17 electrons. It exists as a diatomic molecule (Cl₂) in its elemental form.
* Chlorine ion (Cl⁻): This is a negatively charged form of chlorine, with 17 protons and 18 electrons. It gains an extra electron to achieve a stable electron configuration, making it an anion.
How to tell the difference:
* Charge: A chlorine atom has no net charge, while a chlorine ion has a negative charge.
* Context: If you're dealing with a molecule or compound containing chlorine, the chlorine is likely an ion. For example, in sodium chloride (NaCl), chlorine exists as Cl⁻.
* Chemical reactions: Chlorine atoms can gain electrons to form chloride ions during chemical reactions.
In summary: Chlorine can exist as a neutral atom (Cl) or a negatively charged ion (Cl⁻) depending on its state and involvement in chemical reactions.
