Radium emits which of the following radiations: September 2007, 2010

Ans. D All of the above Radium was discovered in 1898 by French physicist and Nobel laureate Marie Curie in pitchblende (a uranium andradiumbearing mineral). There is about 1 gram of radium in 7 tons of pitchblende.Elemental radium was isolated by Madam Merry Curie in 1911 Radium is a naturally radioactive, silvery-white metal when freshly cut. It blackens on exposure to air. Purified radium and some radium compounds glow in the dark (luminesce). The radiation emitted by radium can also cause ceain materials, called "phosphors" to emit light. Mixtures of radium salts and appropriate phosphors were widely used for clock dials and gauges before the risks of radium exposure were understood. Metallic radium is highly chemically reactive. It forms compounds that are very similar to barium compounds, making separation of the two elements difficult. The various isotopes of radium originate from the radioactive decay of uranium or thorium. Radium-226, the most common isotope, is an alpha emitter, with accompanying gamma radiation, and has a half-life of about 1600 years. Radium-228, is principally a beta emitter and has a half-life of 5.76 years. Radium-224, an alpha emitter, has a half life of 3.66 days. Radium decays to form isotopes of the radioactive gas radon, which is not chemically reactive. Stable lead is the finalproduct of this lengthy radioactive decay series.