Chlorine has 18 neutrons, 17 electrons and 17 protons. Chlorine is a halogen gas that has the atomic weight of 35.43 grams per mole. This toxic gas has a density of 3.21 grams per cubic centimeter.
Although chlorine was discovered in 1774 by Carl Wilhelm Scheele, Humphry Davy is credited for recognizing chlorine as an element in 1810. Chlorine is not present in nature in pure form. It is found in minerals like halite and in sodium chloride from which it is extracted through the process called electrolysis.
This gas received its name from its color, which in Greek is "chloros" and means yellow-green. Chlorine is a toxic gas that can cause death in very high doses. Some applications of chlorine are for insecticides, water purification and cleaning solvents.