Chemistry old nerds names

yea

Democritus

• Different particles give each material it’s own unique properties

• Mixing different atomos make new materials

Aristotle

• Believed all things were made of 4 “elements”

• The elements were:  earth, air, fire and water

• This theory was accepted for 2000 years

John Dalton

• Billiard Ball Model

• All atoms of a particular element are identical in mass

• No 2 elements have atoms of the same mass

• Atoms were solid spheres

J.J. Thompson

• Raisin Bun or Plum Pudding Model

• The atom is a positively charged sphere in which negatively charged electrons were embedded like raisins in a bun

• The whole atom has no electric charge

Hantaro Nagaoka

• Hantaro Nagaoka (1904) was a Japanese physicist

• Refined the model of the atom 

• Proposed the atom as a positive sphere (nucleus) and electrons orbiting in a ring, much like a miniature solar system

Rutherford

• Atoms were mainly empty space but the core was a tiny positively charged centre, called the nucleus

Neils Bohr

• Electrons move in circular orbits called electron shells

• Electrons jump between these shells by gaining or losing energy

• Bohr Diagram

James Chadwick

• The nucleus contained positively charged particles called protons and neutral particles called neutrons

• A proton and a neutron have approximately the same mass

Quantum Mechanics Theory

The theory states that electrons are found in a charged cloud around the nucleus