Question

The chemical elements, caesium, and rubidium, both of which are metals, were discovered by splitting:

• A. hard ores in a furnace
• B. light in a spectroscope
• C. the atom in a cyclotron
• D. salt solution by an electric current

Answer 1

The correct option is B light in a spectroscope

• Cesium was discovered by Robert Wilhelm Bunsen and Gustav Robert Kirchhoff, German chemists, in 1860 through the spectroscopic analysis of Durkheim mineral water. They named cesium after the blue lines they observed in its spectrum.
• Rubidium was discovered in 1861 by Robert Bunsen and Gustav Kirchhoff, in Heidelberg, Germany, in the mineral lepidolite through spectroscopy. Because of the bright red lines in its emission spectrum, they chose a name derived from the Latin word rubidus, meaning "deep red".
  
• Bunsen and Kirchhoff had developed the spectroscope. The device was based on a prism which separated light from a flame into a rainbow of colors.
  
• Hence option B is correct answer.