posted by sam .
in an atom electrons move in definite orbits around the nucleus much like planets cirlce the sun.
who said this - I think Bohr
Bohr is right
An atom is made of positively charged pudding like material through whic hnegatively cahrged particels are scattered
I put thompson -
now I am not sure after reading winnepedia maybe rutherford??
The J.J. Thomson (note the spelling) model was the pudding model. Rutherford was a student of Thomson and discovered alpha particles. In experiemnts after graduating, Rutherford noted that his alpha particle scattering experiments could not be explained by the Thomson model; therefore, he proposed the idea that the mass of the atom was at the center, the center was positively charged, and electrons were somewhere outside the nucleus. (He didn't know about neutrons--they were not discovered until later).