17 - Chlorine diatomic nonmetal
Discovered by Carl Wilhelm Scheele in 1774
Chlorine 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.
Periodic table
| Shell | Electrons | Orbitals |
|---|---|---|
| 1 | 2 | 2 in 1s |
| 2 | 8 | 2 in 2s + 6 in 2p |
| 3 | 7 | 2 in 3s + 5 in 3p |
Electron shells
pale yellow-green gas Appearance
35.5 u Atomic Mass
1 Å Atomic Radius
239 K Boiling Point
17 Group
-1, 1, 3, 5, 7 Common Oxidation States
1.02 Å Covalent Radius
0.0032 g/cm³ Density
349 kJ/mol Electron Affinity
1s2 2s2 2p6 3s2 3p5 Electron Configuration
[Ne] 3s2 3p5 Electron Configuration (semantic)
3.16 Electronegativity
17 Electrons
13 eV First Ionization Energy
-1 ICSD Oxidation States
1251.2, 2298, 3822, 5158.6, 6542, 9362, 11018, 33604, 38600, 43961, 51068, 57119, 63363, 72341, 78095, 352994, 380760 kJ/mol Ionization Energies
172 K Melting Point
99 Mendeleev Number
3 Number of Shells
7 Electron Valency
18 Neutrons
17 Atomic Number
11 Number of Isotopes
-1, 1, 2, 3, 4, 5, 6, 7 Oxidation States
3 Period
Gas Phase
17 Protons
2, 8, 7 Electron Shell Occupations