-
Hydrogen
Cavendish discovered hydrogen -
Atoms
John Dalton defined atoms and assigned them to each element -
Potassium
David conducted his first experiment with potassium -
Spectroscope
Invented by Robert Wilhelm Bunsen -
Nucleus of the atom
Ernest Rutherford looked inside the atom for the first time. -
X-ray spectra
Henry Moseley discovered a systematic relation between wave length and atomic number