Chlorine is one of the halogens, the second most abundant on Earth, and has many uses. However, it also has certain harmful effects. Chlorine is one of the atoms in a toxin that some South American frogs have in their skin. Apparently, it can paralyze or even kill large animals. Golden dart frogs are actually thought to be one of the most toxic animals on Earth. The frogs have adapted in order to prevent poisoning themselves. Scientists believe some poison dart frogs have developed what is known as toxin sponge molecules. These stop the toxin binding onto the frogs’ own cells. As a result they are immune to their own poison.
In the United States, chlorine is added to chicken carcasses to get rid of faecal contamination! It also destroys ozone – just one chlorine atom can destroy as many as 100,000 ozone molecules!
GCSE Science students – you need to be able to describe and explain the properties of the halogens. Our new guide, “How to work with Halogens” can help. Included, as always are questions to try, and answers to check your understanding.
To see the guide, click on the picture below. 
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