History_of_the_atom

Solid Sphere Model

Proposed by John Dalton; suggests that substances are made of small hard spheres called atoms that cannot be divided.

Plum Pudding Model

Modified by J J Thomson; describes an atom as a sphere of positive charge with negatively charged electrons embedded within it.

Nuclear Model

Developed by Ernest Rutherford; suggests that the mass of the atom is concentrated in the nucleus, which has a positive charge.

Planetary Model

Proposed by Niels Bohr; suggests that electrons orbit the nucleus in shells at set distances.

Atomic Model

Developed by James Chadwick; includes neutrons in the nucleus among protons and electrons.

Electron

A negatively charged particle found within an atom.

Nucleus

The center of an atom, containing protons and neutrons and carrying a positive charge.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A neutral particle found in the nucleus of an atom.

Alpha Scattering Experiment

An experiment conducted by Ernest Rutherford that demonstrated the structure of the atom by firing alpha particles at gold foil.