atom history

• Ernest rutherford?

  alpha particle experiment

  discover the positively charged nucleus with a cloud of electrons surrounding with the rest having empty space
• bohr?

  electrons are in shells which orbit the nucleus in a fixed distance

  made the nuclear model
• John dalton?

  atoms are solid spheres
• jj thompson?

  atoms weren't solid spheres but contained electrons

  made the plum pudding model
• mendeleev?

  left gaps in the periodic table for new elements

  he ordered the elements in atomic weight