ATOMIC TIMELINE

DEMOCRITUS 460 BC

ATOMOS THEORY

• Atoms are indestructable
• Atoms are solids
• Atoms are invisible
• Atoms are homogenous
• Atoms come in different sizes

ARISTOLE 384-322 BC

4 ELEMENTS

• Fire is hot and dry
• Air is hot and wet
• Water is cold and wet
• The earth is cold and dry
• He related the 4 elements to two sensible qualities

DALTON 1766-1844

BILLIARD BALL MODEL

• Atoms are the smallest partical of a element
• Atoms have different masses
• Atoms are indestructible like a billiard
• A billiard is solid like a atom
• A billiard can not be broken down like a atom

THOMSON 1856

PLUM PUDDING MODEL

• a positive charged substance fills atoms
• Thomson did the cathocle ray experiment
• The negative charge was surrounded by positve charge
• The pudding was positive charge
• The raisins were the negative charge

RUTHERFORD 1871-1937

POSITIVELY CHARGED NUCLEUS

• Rutherford did the gold foil experiment
• The center of a atom is the nucleus
• The nucleus has a high charge
• The gold foil showed that the center is the nucleus
• The atom isn't a singular particle

MILLIKAN 1868-1953

MASS/CHARGE IF AN ELECTRON

• Millikan did the oil drop experiment
• The exper. was to test the charge and mass
• He determined the size of the charge on the electron
• He started out testing water but chsnged it to oil
• The water evaporated too fast compared to the oil

CHADWICK 1891-1974

PROTON AND NEUTRON

• Protons and neutrons make up an atom
• The proton is a baryon
• Protons and electrons are the same size
• Protons and electrons attract each other
• Protons have a positive charge