Chlorine Atoms
Definition and meaning of Chlorine Atoms in chemistry.
Chlorine atoms are individual atoms of the element chlorine (atomic number 17, symbol Cl), a halogen with seven valence electrons that make it strongly electronegative and highly reactive.
In more detail
Because a chlorine atom needs only one more electron to complete its octet, it acts as a powerful oxidizing agent, readily gaining an electron to form the chloride ion (Cl⁻) or sharing an electron pair to form a single covalent bond. Free chlorine atoms are reactive radicals that do not persist in isolation; under normal conditions chlorine exists as diatomic Cl2 gas or as chloride salts such as sodium chloride. Chlorine has two stable isotopes, ³⁵Cl and ³⁷Cl, which combine to give it a standard atomic weight of about 35.45. In the stratosphere, chlorine atoms released from chlorofluorocarbons act as catalysts in ozone-depletion reactions.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Cl |
| Atomic Number | 17 |
| Electron Configuration | [Ne] 3s² 3p⁵ |
In the reaction 2 Na + Cl2 → 2 NaCl, each chlorine atom gains one electron from a sodium atom, becoming a Cl⁻ ion and forming ionic sodium chloride.
Frequently asked questions
Is a chlorine atom the same as chlorine gas?
No. Chlorine gas (Cl2) consists of two chlorine atoms joined by a covalent bond; a single free chlorine atom is an unstable radical that is not found in isolation under ordinary conditions.
Why does a chlorine atom usually form a -1 ion?
A chlorine atom has seven valence electrons, so gaining just one more completes a stable octet, producing the chloride ion (Cl⁻), as seen in compounds like NaCl.