Oxygen is element 8, a non-metal of the p block, in group 16, period 2. Its ground-state configuration is [He] 2s2 2p4, and it usually shows the oxidation states -2, -1, 0.
It was discovered in 1774, by Priestley and Scheele.
Name origin: from the Greek oxy-, both 'sharp' and 'acid', and -gen, meaning 'acid-forming'.
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