17 · Cl
Chlorine
Prepared by Scheele in 1774 and identified as an element by Davy in 1810.
Identity
- Atomic number
- 17
- Symbol
- Cl
- Canonical name
- Chlorine
- Category
- halogen
- Group
- 17
- Period
- 3
- Block
- p
Properties
These quantities come from the Periodic Table JSON compilation. They have not yet been checked, one by one, against CIAAW atomic weights or NIST measurements. A value marked estimated is not a measurement.
- Atomic mass
- 35.45 u
- Electron configuration
- [Ne] 3s2 3p5
- Electrons per shell
- 2, 8, 7
- Standard state
- gas
- Density
- 3.2 g/L
- Melting point
- 171.6 K
- Boiling point
- 239.11 K
- Electronegativity
- 3.16 Pauling
- First ionization energy
- 1,251.2 kJ/mol
- Electron affinity
- 348.575 kJ/mol
History
A green gas
Observation · confirmed · 1774
Scheele prepares chlorine and takes it for an oxygenated compound. Observing the gas is not proving that it is an element.
An element in its own right
Identification · confirmed · 1810
Davy shows that chlorine contains no oxygen and must be counted as an element.
Etymology
- Theme
- color
- Language
- grec
- Root
- chloros
- Meaning
- greenish yellow
Scientists
Places and institutions
- London — historical setting : United Kingdom — present country : United Kingdom
See also
Sources
- IUPAC, Periodic Table of the Elements
- Bowserinator, Periodic Table JSON. Compilation secondaire d’où viennent les grandeurs physiques importées (masse, densité, températures, énergies). Elles ne sont pas revérifiées une à une auprès du NIST ou de la CIAAW.
- John Emsley, Nature’s Building Blocks: An A–Z Guide to the Elements