History of Atomic Theory

Chadwick, Worked with Rutherford to discover particles with no charge - called neutrons. Neutrons are also found in the nucleus

Democritus, Matter is formed of small pieces that could not be cut into smaller parts called "atomos" meaning uncuttable

Thomson, Atoms are made mostly out of (+) charged material, like dough in a bun. The (-) charged electrons are found inside the (+) dough

Dalton, 1. Atoms are tiny, invisible particles 2. Atoms of one element are all the same. 3. Atoms of different elements are different. 4. Compounds form by combining atoms.

Rutherford, Atoms have (+) particles in the center, and are mostly empty space. (+) particles called protons, the center of atoms called the nucleus.

Bohr, Improved on Rutherford's model - proposed that electrons move around the nucleus in specific layers, or shells. Every atom has a specific number of electron shells.

Schrodinger, and Heisenberg They discovered that electrons don't travel in definitive paths, however there are regions inside the atom where electrons are likely to be found. These regions are called electron clouds

Demetrius, this way