Cl
Chlorine is a highly reactive halogen gas used widely for water purification.
Physical Properties
| Atomic Mass | 35.45 u |
| Density | 0.003214 g/cm³ |
| Melting Point | 171.6 K |
| Boiling Point | 239.11 K |
| Appearance | Pale yellow-green gas |
| State at Room Temp | Gas |
Chemical Properties
| Electronegativity | 3.16 (Pauling) |
| 1st Ionization Energy | 1251.2 kJ/mol |
| Electron Affinity | 349.0 kJ/mol |
| Oxidation States | -1, +1, +2, +3, +4, +5, +6, +7 |
Atomic Properties
| Electron Configuration | [Ne] 3s2 3p5 |
| Atomic Radius | 79.0 pm |
| Covalent Radius | 102.0 pm |
| Van der Waals Radius | 175.0 pm |
Discovery
| Discovered By | Carl Wilhelm Scheele |
| Discovery Year | 1774 |
| Location | Uppsala, Sweden |
| Named After | Greek 'chloros' meaning pale green |
About Chlorine
Chlorine is a yellow-green gas with a pungent odor. It is the third most abundant element in the ocean. Chlorine water treatment has saved countless lives from waterborne diseases. Combined with sodium, it forms table salt.
Uses & Applications
Water purification, PVC plastic production, bleach, disinfectants, hydrochloric acid, and pesticides.
Fun Fact
The introduction of chlorine water treatment in the early 1900s virtually eliminated typhoid and cholera from treated water supplies.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 35 | 0.7576% | - | Yes |
| 37 | 0.2424% | - | Yes |
Electron Configuration
[Ne] 3s2 3p5