17Cl35.45
Chlorine
Halogen
Gas at STP
Period 3Group 17Block PDiscovered 1774
[Ne]3s2 3p5
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.
📖 Read more on Wikipedia →Emission Spectrum
Atomic Properties
| Atomic Number | 17 |
| Atomic Mass | 35.45 u |
| Electron Configuration | [Ne]3s2 3p5 |
| Oxidation States | +7, +5, +1, -1 |
| Electronegativity | 3.16 (Pauling) |
| Atomic Radius | 175 pm |
| Ionization Energy | 12.968 eV |
| Electron Affinity | 3.617 eV |
| Block | P |
Physical Properties
| Appearance | pale yellow-green gas |
| Standard State | Gas |
| Melting Point | 171.65 K (-101.5 °C) |
| Boiling Point | 239.11 K (-34.0 °C) |
| Density | 0.003214 g/L |
| CPK Color | #1FF01F |
Classification
| Category | Halogen |
| Group Block | Halogen |
| Period | 3 |
| Group | 17 |
| Block | P |
Discovery
| Year Discovered | 1774 |
| Discovered By | Carl Wilhelm Scheele |
| Electron Shells | 2, 8, 7 |