Answer:
Step-by-step explanation:
J. J. Thomson Electrons are scattered within the atom.
J.J. Thomson carried out experiment on the discharge tube in 1897 which led to the discovery of electrons as a subatomic particle. During this time, the whole atom was thought to be made of only electrons.
John Dalton Atoms are the smallest unit of an element.
John Dalton in 1808 proposed that atoms are the smallest indivisible particles of an element.
Ernest Rutherford Protons are at the center of an atom.
In 1911, Ernest Rutherford performed experiments using gold foil. He discovered that an atom is made up of a massive center made up of positively charged particles called protons.
Niels Bohr Electrons are in orbital levels.
Bohr in 1913 suggested that electrons are in specific spherical orbits around the central nucleus.