1. Chapter 4 The Atom – Part 1

2. What is the atom? Sulfur

3. What is the atom? Lead

4. An atom is the smallest particle of an element that retains that element’s properties. From the Greek “a-tomos” which means “not divisible”. The concept of the atom was first proposed in Greece over 5000 years ago.

5. Democritus First proposed the concept that matter was not continuous but was instead made up of tiny particles he termed the “atoms”.

6. Aristotle Believed in the four elements: Earth, Air, Fire and Water. Proposed a fifth element “ether”. Because of Aristotle’s vast influence on later generations his ideas would persist until the Renaissance. (Philosophy vs. Science)

7. Sir Francis Bacon – Teacher Facts Member of British Parliament and Attorney General of England – charged with corruption – many think wrongly charged by his political enemies. Changed philosophy to science - deductive to inductive reasoning ( ideas and feelings to fact). Died of pneumonia experimenting with snow – jumped out of his carriage in the mountains to experiment on it.

8. Sir Francis Bacon (1561-1626) Father of “Inductive Reasoning”. “Knowledge is Power”

9. Robert Boyle – Teacher Facts Wrote “The Skeptical Chymist” in 1661 – appealed for experimentation to be the basis of the new science of “chemistry”. Influential in moving alchemy to chemistry.

10. Robert Boyle (1627 – 1691) Robert Boyle is generally regarded as the first modern chemist

11. Antoine Lavoisier (1743 – 1794) Father of Modern Chemistry. Law of Conservation of Mass. Abolished the Phlogiston Theory. Recognized and named oxygen and hydrogen. Introduced the metric system. Wrote the first extensive list of elements.

12. Antoine Lavoisier (1743 – 1794) Declared a traitor during “The Reign of Terror”. “It took them only an instant to cut off his head, but France may not produce another like it in a century” (LaGrange).

13. John Dalton (1766 – 1844) Proposed the first scientifically supported atomic theory.

15. J. J. Thomson (1856 – 1940) Credited for the discovery of the electron and of isotopes, and the invention of the mass spectrometer.

16. James Chadwick (1891 – 1974) Discovered the neutron. Paved the way for nuclear power and the nuclear bomb.

17. Lord Ernest Rutherford – Teacher Facts Died in hospital from complications of a hernia. British protocol required that he be operated on by a “titled” doctor since he was a “peer”. This delay cost him his life.

18. Lord Ernest Rutherford (1871 – 1937) Discovered the nucleus of the atom. Pioneered the orbital theory of the atom.

19. Rutherford’s Gold Foil Experiment

21. Rutherford’s Nuclear Model of the Atom The nucleus is very small, dense, and positively charged. Electrons surround the nucleus. Most of the atom is empty space