Definition of antemortem in the Definitions.net dictionary. Meaning of antemortem. What does antemortem mean? Information and translations of antemortem in the most comprehensive dictionary definitions resource on the web.
Boron is a chemical element. It is a metalloid. Its chemical symbol is B and its atomic number is 5. It was first discovered in 1808 by the efforts of French physicist Joseph-Louis Gay-Lussac, French chemist Louis-Jaques Thenard. They reacted sodium with boric acid to separate boron element. Later it was isolated by British chemist Sir Humphry Davy independently.
In 1869 Russian chemist Dimitri Mendeleev started the development of the periodic table, arranging chemical elements by atomic mass. He predicted the discovery of other elements, and left spaces open in his periodic table for them.In 1886 French physicist Antoine Bequerel first discovered radioactivity.Thomson student from New Zealand Ernest Rutherford named three types of radiation; alpha, beta and gamma rays.n 1894 Sir William Ramsay and Lord Rayleigh discovered the noble gases, which were added to the periodic table as group 0. In 1897 English physicist J. J. Thomson first discovered electrons; small negatively charged particles in an atom. John Townsend and Robert Millikan determined their exact charge and mass.