Question

which idea did john dalton include in his atomic theory? a. all atoms are the same size. b. atoms of the same element are identical. c. each atom has a dense, positive nucleus. d. atoms can gain or lose electrons to become ions.

Answer 1

It might be c, because he came up with the plum pudding model.  or it might be that atoms of the same element are identical, but that's not true cuz ions are different and isotopes are different.