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.
Rubidium is used as a getter in vacuum tubes because it combines with and removes trace gases. It is also a component in photocells and has been used in making special glasses. Rubidium has been considered for use in ion engines in space shuttles, because it can be easily ionized.Cesium, however, is more efficient.t is a soft, silvery-white metallic element in the alkali group. [See Periodic Table of the Elements ]. Rubidium is the second-most electropositive and alkaline element. As with other alkali metals, it forms amalgams with mercury and alloys with gold, cesium, sodium and potassium.