History of the Atom

Which of the following observations led Thomson to conclude that cathode ray particles were negatively charged?

• He observed that negatively charged plates repelled the rays.

• He observed that a metal plate exposed to cathode ray particles became positively charged.

• He observed that cathode ray particles traveled in a straight path through electric fields.

• He observed that positively charged plates repelled the rays.

According to Niels Bohr, electrons gain energy and emits electromagnetic radiation(energy). These electrons are found in-?

• energy levels

• nucleus

• only in the gold foil

• protons

In 1897, J.J. Thomson used a device like the one shown to discover that cathode rays were

streams of —

• photons

• electrons

• protons

• ions

Who discovered electrons?

• Dalton

• Rutherford

• Thomson

• Bohr

Who discovered that electrons exist in energy levels or shells?

• Dalton

• Rutherford

• Thomson

• Bohr

Which of these is not one of Rutherfords conclusions...?

• nucleus is small

• nucleus is dense

• nucleus is positively charged

• nucleus has no charge

Rutherford used what to make his discoveries?

• Gold foil experiment

• cathode ray tube

• Jimmy neutron model

Who discovered that the atom is mostly empty space?

• Dalton

• Rutherford

• Thomson

• Bohr

Who discovered atoms?

• Dalton

• Rutherford

• Thomson

• Bohr

Thomson used what to make his discoveries?

• Gold foil experiment

• cathode ray tube

• Jimmy neutron model