Atoms of the same element are identical. The atoms of the one element are different from those of any other element. 3. Atoms of different elements can physically mix together or can chemically combine in simple whole-number ratios to form compounds.
iridium (symbol Ir) Silver-white, metallic element discovered in 1804 by the English chemist Smithson Tennant. A platinum-type metal, iridium is hard and brittle and the most corrosion-resistant metal. very rare element (0.0001 ppm of Earth 's crust), iridium is found in the naturally occurring alloys osmiridium (approximately 50% iridium) and iridiosmium (approximately 70% iridium) in Alaska and South Africa. It is obtained by igniting ammonium chloroiridate, (NH 4) 3 IrCl 6, in hydrogen atmosphere.
Discovery of Iridium. Iridium was discovered in 1803, by English chemist Smithson Tennant in London. He found it in the residue left when crude platinum had been dissolved in aqua regia (a mixture of hydrochloric acid and nitric acid). Smithson Tennant also discovered osmium at the same time.ource: Iridium is found in natural alloys with platinum and osmium in alluvial deposits. Commercially, iridium is recovered as a by-product from the nickel mining industry. Isotopes: Iridium has 34 isotopes whose half-lives are known, with mass numbers from 165 to 198.