Element Argon Ar, Noble Gas. obtained from chemical compounds, in having a somewhat greater density.

Element Bromine, Br, Halogene. The vapour of bromine is very heavy. If a small bulb filled with bromine be broken, or if, by means of a pipette, a drop of bromine be placed at the bottom of a large, empty bottle, it is seen that the brown-yellow vapour produced remains at the bottom and sways heavily when the bottle is moved. Only after standing undisturbed for a considerable time does the bromine.

Element Fluorine, F, Halogene. To the group of halogen elements there must also be added the element fluorine, which differs in its properties more widely from the other three than these from one another. It exhibits, however, still fewer relationships with the rest of the elements, and is, therefore, most suitably classed along with the halogens. Compounds of fluorine are fairly widely distributed in nature. It occurs in small quantity in many rocks, and its calcium compound, fluorspar, is a very ab.

Element Krypton, Kr, Noble Gas. From Greek κρυπτον, krypton. Abundance in air is about 1. Of air contains 1 sm.

Element Neon, Ne, Noble Gas. Was discovered in 1898 by Scottish chemist William Ramsay and English chemist Morris W. Travers, when Ramsay chilled a sample of the atmosphere until it became a liquid, then warmed the liquid and captured the gases as they boiled off. The spectral analysis showed the presence of new three gases which were krypton, xenon, and neon. I should like to call it Novum. Is supplied by natural waters.

Element Oxygen, O, Non Metal. Joseph Priestley was generally acknowledged as the discoverer of oxygen. By heating it via the sun rays focused on it by powerful lens. However Priestley first did not realize that he discovered a new substance. He supposed that he just separated one of the components. Priestley informed Antoine Laurent Lavoisier about his discovery. Is the most abundant element on the Earth; i.

Element Selenium, Se, Non Metal. Whereas the amorphous selenium does not conduct the electric current to a measurable extent, the property of conductivity is possessed by the crystalline form. Hydrogen selenide is the hydrogen acid of selenium in the same sense as hydrogen sulphide is the hydrogen acid of sulphur; its aqueous solution contains the ions Se. By heating selenium with iron filings, and to treat this with hydrochloric acid. In a manner perfectly analogous to the prep.