Origin of name: from the Latin word "rubidius" meaning "dark red" or "deepest red". Atomic Number: 37 Symbol: Rb Atomic Weight: 85. 4678 Say what? Rubidium is pronounced as roo-BID-ee-em. Discovery: R. Bunsen, G. Kirchoff 1861 (Germany), discovered rubidium in the mineral petalite via its dark red spectral lines. Element Classification: Alkali Metal Density (g/cc): 1. 532 Melting Point (K): 312. 2 Boiling Point (K): 961 Appearance: soft, silvery-white, highly reactive metal Atomic Radius (pm): 248 Atomic Volume (cc/mol): 55. 9 Covalent Radius (pm): 216 Ionic Radius: 147 (+1e) Specific Heat (@20°C J/g mol): 0. 360 Fusion Heat (kJ/mol): 2. 0 Evaporation Heat (kJ/mol): 75. 8 Pauling Negativity Number: 0. 82 First Ionizing Energy (kJ/mol): 402. 8 Oxidation States: +1 Lattice Structure: Body-Centered Cubic Lattice Constant (A): 5. 590 CAS Registry Number: 7440-17-7 Properties: Rubidium may be liquid at room temperature. It ignites spontaneously in air and reacts violently in water, setting fire to the liberated hydrogen. Thus, rubidium must be stored under dry mineral oil, in a vacuum, or in an inert atmosphere. It is a soft, silvery-white metallic element of the alkali group. Rubidium forms amalgams with mercury and alloys with gold, sodium, potassium, and cesium.
Rubidium glows red-violet in a flame test. Rubidium Trivia: • Rubidium melts just a little above body temperature. • Rubidium was discovered using spectroscopy. When Bunsen and Kirchoff examined their sample of petalite, they found two red spectral lines deep into the red part of the spectrum. They named their new element rubidium after the Latin word rubidus meaning 'deepest red'. • Rubidium is the second most electropositive element. • Rubidium can be used to give fireworks a red-violet color. • Rubidium is the 23rd most abundant element in the Earth's crust. Rubidium chloride is used in biochemistry as a biomarker to track where potassium is taken up by living organisms. • The hyper-fine electron structure of Rubidium-87 is used in some atomic clocks to maintain accuracy. • The isotope Ru-87 was used by Eric Cornell, Wolfgang Ketterle, and Carl Wiemen to produce a Bose-Einstein condensate. This earned them the 2001 Nobel Prize in Physics. Reference: • http://chemistry. about. com/od/elementfacts/a/rubidium. htm • http://www. lenntech. com/periodic/elements/rb. htm • http://www. webelements. com/rubidium/ • http://education. jlab. org/itselemental/ele037. html [pic]
