In some browsers, after entering your weight you may have to click outside the text entry box to make the calculation work. Elements for which there are no data will always give a value of zero for the weight, no matter what you put in the weight box. Here are a few notes about the hazards and risks associated with chlorine. Chlorine gas is very toxic because of its strong oxidising nature. Even low concentrations of chlorine gas attack eyes, throats, and lungs with painful effects.
Chloride is relatively harmless.