The Atom and EMR

Dalton

Devised the first atomic theory

Said that all atoms of an element are identical in size. Mass and other properties

Thomson

Discovered the first subatomic particle

Showed cathode rays are composed of negative particles

Conducted an experiment using cathode ray tubes

Concluded all elements contain electrons

Bohr

The first to suggest electrons had a fixed energy

Rutherford

Discover the nucleus

Determined that the mass of an atom was concentrated in the center

Erwin

Treated electrons as waves

neutrons and mass number

Isotopes of the same element have different..

Ion

An atom that has gained or lost electrons and carries a net electrical charge is called an…