Democritus was first to suggest exsistence of atoms. He believed atoms were indestructible and indivisible.
Dalton's Atomic Theory.
John Dalton pictures atoms as tiny indestructible particles, with no internal structure.
Observed a cathode ray tube and found rays traveling in the direction opposite of the cathode ray. This was evidence for a positively charged particle called a proton.
Discovered the electron. This later leads to his "plum-pudding" model. He pictures electrons embedded in a sphere of positive electrical charge.
Suggests that an atom has a central nucleus and that electrons move in orbit.
Atoms have a small, dense, positively charged nucleus with electrons moving around it.
Believed the electron moves in a circular orbit at fixed distances from the nucleus.
Did experiments to find quantity of charge carried by an electron. He ended up calculating the mass of an electron.
Proposes that moving particles like electrons have some properties of waves. After a few years experimental evidence supported this idea.
Developed mathematical equations to describe the motion of electrons in atoms, leading to the electron cloud model.
Confirms the existence of neutrons, which have no charge.
Battle of Samos. Greek city states made peace with the Persian Empire.
Great fire in Bombay, India. Ohio becomes the end of the state
Meteorites fall in L'Aigle France. First horses arrive in Hawaii.
Slavery abolished in Cuba. China takes over Burma.
Japan adopts Gold Standard. World's first car dealer opens in London.
Russian-Japanese War begins. First airplane flight to last more than five minutes.
First International Women's Day. South Pole first reached by Norwegian Roald Amundson.
First drive up gasoline station opens. Greece formally takes possession of Crete.
US Senate agrees to participate in World War 1. Bulgaria declares war on Romania.
Draft Law passes. Time Magazine debuts.
Italian-Spanish peace treaty signed. Germany joins League of Nations.
Japan and China sign a peace treaty. Japanese forces attack and occupy Shanghai.