In the gold foil experiment, most of the positively charged alpha particles passed through the gold foil, but some were deflected or bounced back. What did we conclude because of this?

The cathode-ray tube was used to discover the ____ by ____.

What were J. J. Thomson's major contributions to the atomic theory?

Which scientist measured the charge on an electron as 1.602 x 10-19 Coulombs?

Place the following atomic models in order, from earliest to latest:

What are electrons?

This model this model was the first to show a nucleus, consisting of protons and neutron. Electrons surround the nucleus but are not shown in distinct energy levels.

This model added on to previous models by showing electrons existed at certain "energy levels". However it does not accurately show what those levels look like.

This model was developed after J.J. Thompson discovered electrons, a particle smaller than an atom. It shows electrons floating freely in a positive region.

Aristotle and other early Greek philosophers thought that matter was composed of four elements: air, earth, fire, and water(T/F)

Dalton developed the first scientifically tested atomic theory. (T/F)

Who was the first to propose that matter consist of indivisible particle of matter called atoms?

Who established that "electrons move around the nucleus at fixed distances called orbitals or shells"?