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.
Iridium is one of the rarest elements in Earth's crust, with annual production and consumption of only three tonnes. 191 Ir and 193 Ir are the only two naturally occurring isotopes of iridium, as well as the only stable isotopes; the latter is the more abundant of the two.he most stable of these is 192m2 Ir, which decays by isomeric transition with a half-life of 241 years, making it more stable than any of iridium's synthetic isotopes in their ground states. The least stable isomer is 190m3 Ir with a half-life of only 2 Âµs.