Chlorine (Cl)
Chlorine (Cl, element 17) is a halogen in group 17, period 3. Atomic mass 35.453, electron configuration [Ne] 3s² 3p⁵, uses and facts.
About Chlorine
Chlorine is a halogen with the symbol Cl and atomic number 17. It is a gas at room temperature, and it sits in group 17, period 3 of the periodic table. Chlorine was discovered in 1774 by Carl Wilhelm Scheele.
Chlorine key facts
- Atomic number: 17
- Symbol: Cl
- Atomic mass: 35.453 u
- Category: halogen
- Group: 17
- Period: 3
- State at room temperature: gas
- Electron configuration: [Ne] 3s² 3p⁵
- Electronegativity (Pauling): 3.16
- Melting point: 171.65 K (-101.5 °C)
- Boiling point: 239.11 K (-34.04 °C)
- Density: 0.003214 g/cm³
- Common oxidation states: −1, 0, +1, +2, +3, +4, +5, +6, +7
Electron configuration
The electron configuration of chlorine is [Ne] 3s² 3p⁵. The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells. Chlorine has 7 valence electrons.
Uses of chlorine
- Water purification
- PVC plastics
- Disinfectants
Did you know?
Was used as a chemical weapon in WWI. Now mostly known for keeping swimming pools safe.
Other elements in group 17 and neighbours
Frequently asked questions
What is the atomic number of chlorine?
The atomic number of chlorine is 17, which means every chlorine atom has 17 protons.
What is the electron configuration of chlorine?
The electron configuration of chlorine is [Ne] 3s² 3p⁵.
What group and period is chlorine in?
Chlorine is a halogen in group 17, period 3.
What state is chlorine at room temperature?
Chlorine is a gas at room temperature.
What is chlorine used for?
Chlorine is used for water purification, PVC plastics, disinfectants.