Element of the Issue: Chlorine


SC Staff Writer

Chlorine has an atomic number of 17 and a chemical symbol of Cl. As a pure element at standard temperature and pressure, it is a yellowish-green gas. In this pure form, it is diatomic. However, this form is very uncommon, as chlorine is normally found in compounds in the Earth’s crust.

For an element, it is very electronegative, making it a strong oxidizer. It is a member of a unique group of elements called halogens, all of which are found in the seventeenth column of the periodic table. Halogens as a whole are very reactive, which makes them very unique for chemistry.

There is a distinction that must be made between pure chlorine and chlorine in chemical compounds. As a pure gas, chlorine is highly toxic to humans, but its ionic form is a vital component to all life.

When chlorine forms ions, its properties change dramatically. For example, every table in Dansbury has sodium chloride for our food, which consists of the ionic form of chlorine. Chloride ion is really the only form of chlorine found in any known life; all other forms are generally dangerous and harmful.

For the consumer, chlorine has a lot of uses. It is very useful in sanitation, and can be found in household bleach and swimming pools. It is also found in the intermediate forms of plastics, although the chlorine is gone by the time it reaches us.

Due to its high toxicity, chlorine gas was used during World War I as the first gaseous chemical warfare agent.

There are also some environmental issues surrounding chlorine. Compounds known as chlorofluorocarbons (CFCs) were historically used as household refrigerants.

Unfortunately, they have been found to deplete the ozone layer and contribute to climate change via increased greenhouse effect. They have since been outlawed. However, the process of reaching the atmosphere takes years, and the full effect of CFC use may not have yet been noticed.

Chlorine is a truly an amazing element; deadly by itself, necessary on a daily basis with other atoms.

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