Atom Timeline

Solid Sphere Experiment

• Atoms are like hard spheres

• Atoms are indivisible

• Everything is made of atoms

• Made by John Dalton in 1803

Plum Pudding Model

• Atoms are a positively charged cloud

• they contain tiny negatively charged particles (electrons)

• Discovered that electrons were small part of the atoms

• used a CRT to launch a beam through a magnetic field

• Made by JJ Thompson in 1904

Nuclear Model

• Atoms have a small positively charged center, called a nucleus

• The electrons moved around the nucleus

• Most of the atom is a empty space

• Discovered the Nucleus of the atom

• Gold Foil Experiment

• Made by Ernest Rutherford in 1911

Planetary Model

• Electrons exist at specific energy levels called orbitals

• Electrons orbit around the Nucleus and move in specific patterns

• Made by Niels Bohr in 1913

Quantum Model

• Also called the wave-mechanical model or the electron cloud model

• electron travel as waves around the nucleus, not in circular orbits

• Made by Erwin Schrodinger in 1926