17Cl35.45
Chlorine
Halogen · element 17 · group 17, period 3
Quick facts
| Symbol | Cl |
|---|---|
| Atomic number | 17 |
| Relative atomic mass | 35.45 |
| Category | Halogen |
| Position | group 17, period 3 |
| State at 20 °C | Gas |
| Melting point | -101.5 °C |
| Boiling point | -34 °C |
| Density | 0.003 g/cm³ |
| Electronegativity | 3.16 |
| Electron configuration | [Ne] 3s2 3p5 |
About Chlorine
Chlorine has the symbol Cl and atomic number 17, which means every chlorine atom has 17 protons in its nucleus and, in a neutral atom, 17 electrons. At room temperature it is a gas.
Halogens are in group 7. They have 7 outer electrons, exist as diatomic molecules (like Cl₂), and get less reactive going down the group.
It melts at -101.5 °C and boils at -34 °C.
Explore it
See where chlorine sits, and drag the temperature slider to watch it melt and boil, on the interactive periodic table. Practise with quizzes on OmniEx.