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Chlorine (Cl)

From Wikipedia, the free encyclopediaChlorine is a chemical element with symbol Cl and atomic number 17. It also has a relative atomic mass of 35.5. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine.

Chlorine in the periodic table

Atomic number17
Element categoryNonmetal

Physical properties

Phase at STPGas
Density3.2 g/cm3
Atomic weight35.45 u
Melting point171.6 K
-101.55 °C
-150.79 °F
Boiling point239.11 K
-34.04 °C
-29.272 °F

Atomic properties

Electronegativity (Pauling Scale)3.16
Electron affinity348.575 kJ/mol
Oxidation states−1, +1, +2, +3, +4, +5, +6, +7
(a strongly acidic oxide)
Ionization energies
11251.2 kJ/mol
2 2298 kJ/mol
3 3822 kJ/mol
4 5158.6 kJ/mol
5 6542 kJ/mol
6 9362 kJ/mol
7 11018 kJ/mol
8 33604 kJ/mol
9 38600 kJ/mol
10 43961 kJ/mol
11 51068 kJ/mol
12 57119 kJ/mol
13 63363 kJ/mol
14 72341 kJ/mol
15 78095 kJ/mol
16 352994 kJ/mol
17 380760 kJ/mol

Electron configuration

Elektronkonfiguration (shorthand)[Ne] 3s2 3p5
Electron configuration1s2 2s2 2p6 3s2 3p5
Electrons per shell2, 8, 7


Discovered byCarl Wilhelm Scheele
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