This page describes the reactions of the Period 3 elements from sodium to argon with water, oxygen and chlorine. Sodium has a very exothermic reaction with cold water producing hydrogen and a colourless solution of sodium hydroxide. Magnesium has a very slight reaction with cold water, but burns in steam.
The average fall was 5.5 stories. Of the 115 cats studied, 90 per cent survived, including one cat that fell 32 stories onto a sidewalk and suffered only a mild chest injury and a chipped tooth. Interestingly, cats that fell from 9 or more stories suffered fewer injuries than those falling from lower heights.
Discovery of Oxygen. Oxygen was discovered in 1774 by Joseph Priestley in England and two years earlier, but unpublished, by Carl W. Scheele in Sweden. Scheele heated several compounds including potassium nitrate, manganese oxide, and mercury oxide and found they released a gas which enhanced combustion.