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What ws the first element to be formally discovered?
How many groups did John Newlands divide the 56 elements in?
Who is considered to have started the development of the actual periodic table?
Who predicted the discovery of new elements in the actual periodic table?
French physicist Antoine Bequerel first discovered radioactivity. Rutherford named these three types of radiation...
all the above
What did Marie and Pierre Curie work on?
radiation of uranium and thorium
radiation of carbon and hydrogen
radiation of oxygen and nitrogen
What radioactive element did the curies discover?
uranium and thorium
radium and polonium
What did Sir William Ramsay and Lord Rayleigh discover?
English physicist J. J. Thomson first discovered electrons; small negatively charged particles in an atom.
´Glenn Seaborg identified lanthanides and actinides (atomic number >92), which are usually placed below the periodic table.