Chlorine is element 17, a halogen of the p block, in group 17, period 3. Its ground-state configuration is [Ne] 3s2 3p5, and it usually shows the oxidation states -1, 0, 1, 3, 4, 5, 6, 7.
It was discovered in 1774, by Scheele.
Name origin: the Greek chloros, 'greenish yellow'.
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