Chlorine (Cl)
Chlorine is the 17th element, a halogen in the p-block. Its standard atomic weight is 35.453.
Chlorine
35.453
What the table records
- Atomic number
- 17
- Standard atomic weight
- 35.453
- Group
- 17
- Period
- 3
- Block
- p-block
- Category
- Halogen
- [Ne] 3s2 3p5
- Valence electrons
- 7
- Typical valence
- 1
- Van der Waals radius
- 1.8 Å
- Covalent radius
- 1.02 Å
Molecules containing chlorine
The lightest named structures in this library that contain Cl.
Atomic chlorine
Cl · 35.45 g/mol
Chloride
Cl- · 35.45 g/mol
Hydrochloric Acid
HCl · 36.46 g/mol
Methyl Chloride
CH₃Cl · 50.49 g/mol
Hypochlorite
ClO- · 51.45 g/mol
Monochloramine
H₂ClN · 51.48 g/mol
Hypochlorous Acid
HClO · 52.46 g/mol
Sodium Chloride
ClNa · 58.44 g/mol
Cyanogen Chloride
CClN · 61.47 g/mol
Vinyl Chloride
C₂H₃Cl · 62.5 g/mol
Chloroethane
C₂H₅Cl · 64.52 g/mol
Nitrosyl chloride
ClNO · 65.46 g/mol
How to read these numbers
The standard atomic weight is an average over the isotopes as they occur naturally, which is why it is rarely a whole number. It is the figure a molar mass calculation uses. Work in mass spectrometry wants the monoisotopic mass of a single isotope instead, which is a different number.
The two radii are not the same measurement. The covalent radius is half the distance between two bonded atoms of the element; the van der Waals radius is how close a non-bonded atom gets before repulsion takes over, and is always the larger. Space-filling models are drawn with the second, ball-and-stick models with the first — which is why the same molecule looks so different in the two.