1. History of the Atom

2. Democritus BCE
"The Laughing Philosopher"
If you continue to cut a silver coin in halves you would reach a point in which you could not cut any more, there would be an “uncuttable” particle. He called this the atom.
He said atoms are small, hard particles made of a single particle.
He claimed that atoms are always moving and that they form different materials by joining together.
Born in Abdera into great wealth, gave public lectures to bring in money.

3. John Dalton 1766–1844 Was a teacher in England, he was colorblind.
He used observations and experiments in astronomy to suggest that atoms are tiny hard balls.
He believed that atoms were the fundamental building blocks of nature and could not be split.
Creates an Atomic Theory in 1803.
He lived a modest Quaker life.

4. J.J. Thomson 1856–1940
Discovered there are small particles inside the atom, therefore being able to be split.
He used a Cathode-Ray Experiment in order to show there were negatively charged particles, these are now called electrons.

5. J.J. Thomson 1856–1940
His model showed that most of the atom was positively charged and that the electrons were small particles located throughout the positive material. This came to be the plum pudding model.
Became a physicist by default, he could not raise the money to become a engineer.
He received the Nobel Prize in physics in 1906 and a knighthood in

6. Marie Curie 1867–1934 Daughter of an impoverished school teacher.
Used newly discovered X-rays to discover radioactivity, a word she came up with.
She discovered two new elements, both radioactive, polonium and radium.
Organized portable X-ray machines for WWI.
Had two daughters, Irene also became a chemist, both died of cancer from exposure to radioactive materials.
She won two Nobel Prizes, the first in 1903 in physics, and the second in 1911 in chemistry. She even has a element named after her.

7. Dmitri Mendeleev 1834–1907
Took the 60 known elements at the time and arranged them based on properties that these elements had. He used density, appearance, atomic mass, and melting point.
He noticed that the properties of the elements were periodic. He left blanks for the elements that had not been discovered but should fit into his pattern.
He grew up and lived in Russia. He fought for the modernization of Russia.

8. Ernest Rutherford 1871–1937
A former student of Thomson, he used a Gold Foil Experiment to test Thomson’s ideas.
He found that the most of the atom was empty space. In the center there was a dense region he called the nucleus.
He calculated the diameter of the nucleus was 100,000 times smaller then the diameter of the gold atom.
He was born on a farm in New Zealand and the was the 2nd of 12 children.
He received the Nobel Prize in chemistry for 1908; he was made a knight, then a peer with a seat in the House of Lords; and for the ultimate honor he was buried in Westminster Abbey.

9. Neils Bohr 1885-1965 Worked with Rutherford.
Created a model of the atom.
Stated that electrons moved in definite paths around the nucleus, which were located at certain distances away from the nucleus. The electrons could move from one path to another but not between paths.
Won a Noble Prize in 1922.
He worked on the Manhattan Project in WWII

10. Erwin Schrödinger 1887-1961 Helped create the modern view of the atom.
Also known for the thought experiment, Schrödinger’s Cat.
He stated there is an electron cloud in which the electron was likely to be found.
Created the Schrödinger equation which said that electrons act both like wave and a particle.
Received the Noble prize in 1933.

11. James Chadwick
Was a student of Rutherford then later worked with Rutherford.
Discovered the Neutron. A particle with a neutral charge. Which helped tell the difference between the atomic number and mass number.
Inspired other scientists to discover nuclear fission.
Worked on the Manhattan Project.
Receive the Nobel Prize in He was knighted in 1945.