Atomic Theory

Democritus

• Used philosophy not science 
• Atoms are indivisible
• Atoms are indestructible
• Everything is made up of atoms
• No internal structure

John dalton

• Used science not philosophy
• Atoms are indivisble
• Atoms are indestructible
• Everything is made up of atoms
• No internal structure

jj. thomson

• Discovers electron
• Sphere with positive charge throughout
• Negatively charged particles

Ernest rutherford

• Atoms have small, dense positively charged nucleas
• Electrons move around the nucleus
• Atom surrounded by negative orbiting electrons
• Most of the atom was made up of empty space

neils bohr

• Electron moves in a circular orbit
• An electron can gain or lose energy by changing its orbit
• Energy of an atom changes when it absorbs light
• An electron is found only in specific curcular paths or orbits

erwin schrodinger

• Develops mathematical equations 
• The equations describe the motion of electrons in atom
• Work leads to the electron cloud model
• The nucleus contains protons and neutrons

James chadwick

• Confirms existence of neutrons
• Nuetrons have no charge
• Atomic nuclei contain nuetrons and positevly charged protons
• He proved the existence of neutrons
• He found out that elementary particles devoid of any electrical charge