136 NON-METALS AND THEIR COMBINATIONS. 



State of aggregation. 

 Under ordinary conditions the non-metals show the following states: 



Gases. Liquids. Solids. 



B. P. B. P. F. P. B. P. 



Hydrogen, 253 C. Bromine, 64 C. Phosphorus, 44 C. 280 0. 



Oxygen, 183 Iodine, 11 175 



Nitrogen, 194 Sulphur, 114 400 



Chlorine, - 33 Carbon, | Slightly volatile 



Fluorine, 190 Boron, > in electric 



Silicon, ) furnace. 



Occurrence in nature. 



a. In a free or combined state. 



Carbon in coal, organic matter, carbon dioxide, carbonates. 

 Nitrogen in air, ammonia, nitrates, organic matter. 

 Oxygen in air, water, organic matter, most minerals. 

 Sulphur chiefly as sulphates and sulphides. 



b. In combination only. 

 Boron in boric acid and borax. 



Bromine in salt wells and sea-water as magnesium bromide, etc. 

 Chlorine as sodium chloride in sea-water, etc. 

 Fluorine as calcium fluoride, fluorspar. 

 Hydrogen in water and organic matter. 

 Iodine as iodides in sea-water. 



Phosphorus as phosphate of calcium, iron, etc., in bones and rocks. 

 Silicon as silicic acid or silica, and in silicates. 



Time of discovery. 



Sulphur, ) Long known in the elementary state ; recognized as elements in the 



Carbon, / latter part of the eighteenth century. 



Phosphorus, 1669, by Brandt, of Germany. 



Chlorine, 1774, by Scheele, of Sweden. 



Nitrogen, 1772, by Kutherford, of England. 



Oxygen, 1773, by Scheele, of Sweden ; 1774, by Priestley, of England. 



Hydrogen, 1766, by Cavendish, of England. 



Boron, 1808, by Gay-Lussac, of France. 



Fluorine, 1810, by Ampere, of France 



Iodine, 1812, by Courtois, of France. 



Silicon, 1823, by Berzelius, of Sweden. 



Valence. 1 



Univalent. Bivalent. Trivalent or quinquivalent. Quadrivalent. 



Hydrogen, Oxygen, Nitrogen, Carbon, 



Chlorine, Sulphur. Boron, Silicon. 



Bromine, Phosphorus. 



Iodine, 

 Fluorine. 



1 The valences here given are the ones generally exerted by the elements, but it will be 

 shown later that most of the elements may exhibit a valence differing from the ones here 

 mentioned. 



