The Atom chapter 2

Flashcards about the structure of the atom

Matter

The scientific name for materials, which are made up of small particles.

Diffusion

The spreading of gases or liquids due to the movement of their particles.

Democritus

Greek philosopher who proposed that matter was composed of small, indivisible particles called 'atomos'.

John Dalton

English chemist who proposed an atomic theory stating that all matter is made up of indivisible atoms.

William Crookes

English chemist who used a vacuum tube to discover cathode rays.

Cathode Rays

Rays emanating from the cathode in a vacuum tube, found to travel in straight lines and cause fluorescence.

J.J. Thomson

English scientist who proved that cathode rays consist of negatively charged particles and calculated the charge-to-mass ratio of the electron.

Electrons

Negatively charged particles discovered by J.J. Thomson that are fundamental constituents of atoms.

George Stoney

Professor of Physics who proposed the name 'electron'.

Robert Millikan

American physicist who determined the size of the charge on the electron using the oil drop experiment.

Plum Pudding Model

Model proposed by JJ Thomson with electrons embedded at random.

Ernest Rutherford

Scientist from New Zealand who discovered the nucleus by scattering alpha particles through gold foil.

Alpha Particles

Positively charged particles consisting of two neutrons and two protons, used by Rutherford in his gold foil experiment.

Nucleus

The small, dense, positive core of an atom, discovered by Rutherford.

Protons

Positively charged particles located in the nucleus of an atom, discovered by Rutherford.

James Chadwick

Scientist who discovered the neutron by bombarding beryllium with alpha particles.

Neutrons

Neutral particles located in the nucleus of an atom, discovered by Chadwick.

Sub-Atomic Particles

Particles that are located inside the atom.