DONAVEN AND ADAM

DEMOCRITUS

• Lived in 460-370 BC in Greece
• Discovered that the universe was composed of atoms and that they move
• Atoms cannot be destroyed, differ in size, differ in shape and are moving and invisible.
• He believed infinite number of atoms in everything
• Discovered in about 465BC

JOHN DALTON

• Lived 1776-1844
• Discovered certain gases could be composed of one or more elements
• Found with fixed ratios
• Believed he found the way of atomic theory though gases
• Discovers his theory in 1803

ERNEST RUTHERFORD

• Lived from 1871-1937
• Discovered nuclear structure of an atom
• That particles are fixed into gas atoms and created a postive charge
• Found atomic mass of elements
• Discovered his theory in 1907

NEILS BOHR

• Lived from 1885-1962
• Discovered his theory of hydrogen atom based on his quantum theory
• That electrons jump from orbit to orbit with lower energy
• His theory could explain wave lengths
• Discovered his theory in 1950

J.J. THOMSON

• Lived from 1856-1940
• Discovered the electrons and how they are used in the atomic theory
• That hes found to study the nature of discharge in electrons
• Found what wake up electrons were
• Found his theory in 1894