Symbol Cl Atomic radius: pm 99 Fusion: kJ/Mole 6.4
Name Chlorine Ionic radius: pm (-1)181 Boiling point: C -34
Atomic number 17 Electron affinity 3.61 Melting point: C -102
Atomic weight 35.45 1st  ion potential 12.97 Specific Heat Cap: J/(g K) 0.48
Classification Non-metal Natural form Gas(Cl2) Thermal Cond: W/(cm K) <0.001
Configuration [Ne]3s2p5 Crystal structure - Electrical Cond -
Oxidation states +/-1,3,5,7 Density 3.21 Abundance: mg/kg-crust 145
Electronegativity 3.16 Vaporization: kJ/Mole 20.41    
Chlorine was first prepared from muriatic (hydrochloric) acid and manganese dioxide in 1774 by Carl Wilhelm Scheele.  It was considered a compound until Sir Humphrey Davy showed in 1810 that it could not be decomposed and that muriatic acid consists of two simple substances: hydrogen and a true element that he named chlorine. Uses - bleach, PVC pipe, water purification, cleaning compounds