$\backslash$table$[[$Discovery$,$Scientist$],[\backslash$table$[[$first theorized about the$],[$existence of atoms$]],$Democritus$],[$the law of conservation of mass,Antoine Lavoisier$],[$invented the battery,Alessandro Volta$],[$the modern atomic theory,Dmitri Mendeleev$],[$the periodic table,J$.$ J$.$ Thomson$],[$discovered the electron,Ernest Rutherford$],[\backslash$table$[[$idea that the atom has a$],[$dense nucleus$]],$Niels Bohr$],[\backslash$table$[[$model in which electrons orbit$],[$the nucleus like planets orbit$],[$the Sun$]],$John Dalton$]]$