History of the Atomic Model and Structure

Vocabulary flashcards covering the historical development of atomic models, key scientists, experiments, and subatomic particles from Study Guide 2.1.

Democritus

Early thinker who proposed that matter is made of tiny particles and introduced a specific word to describe atoms.

John Dalton

Scientist who proposed the solid sphere model, representing atoms as solid, indivisible spheres.

Solid sphere model

Atomic model associated with John Dalton in which the atom is represented as a solid, indivisible sphere.

J. J. Thomson

Scientist who discovered the electron using cathode ray experiments and proposed the plum pudding model of the atom.

Plum pudding model

Atomic model developed by J. J. Thomson where electrons are distributed throughout a positively charged sphere.

Ernest Rutherford

Scientist who conducted the alpha-scattering experiment using gold foil and developed the nuclear model of the atom.

Alpha-scattering experiment

Rutherford's experiment using gold foil where most alpha particles passed straight through, proving the atom is mostly empty space, while a small percentage deflected, revealing a small, dense nucleus.

Nuclear model

Atomic model established by Ernest Rutherford showing that the atom is mostly empty space with a small, dense nucleus at the center.

Niels Bohr

Scientist who developed the planetary model of the atom, proposing that electrons occupy specific energy levels or shells around the nucleus.

Bohr (planetary) model

Atomic model in which electrons occupy specific energy levels, or shells, around the nucleus.

James Chadwick

Scientist who discovered the neutron, aiding in the development of the modern atomic model.

Electron

A subatomic particle discovered by J. J. Thomson via cathode ray experiments that occupies specific energy levels or shells around the nucleus.

Neutron

A subatomic particle discovered by James Chadwick that contributed to the development of the modern atomic model.

Nucleus

The small, dense central region of the atom identified by Ernest Rutherford's alpha-scattering experiment.

Shells

Specific energy levels located around the nucleus where electrons are arranged in the Bohr model.