1. Chapter 2 Atoms John Singer, Jackson Community College Chemistry for Changing Times, Thirteenth Edition Lecture Outlines © 2013 Pearson Education, Inc.

2. 2 Chapter 2 © 2013 Pearson Education, Inc. Atoms: The Greek Idea ~384 B.C.E., Aristotle: All matter is composed of four elements and all matter is continuous, not atomistic.

3. 3 Chapter 2 © 2013 Pearson Education, Inc. ~ 450 B.C.E., Leucippus and Democritus Atomos: The point at which matter can no longer be subdivided. Atoms: The Greek Idea

4. 4 Chapter 2 © 2013 Pearson Education, Inc. Early 1700s Lavoisier Law of Conservation of Mass: During a chemical change, matter is neither created nor destroyed. Lavoisier: The Law of Conservation of Mass

5. 5 Chapter 2 © 2013 Pearson Education, Inc. Lavoisier: The Law of Conservation of Mass

6. 6 Chapter 2 © 2013 Pearson Education, Inc. 1799, Proust Law of Definite Proportions: A compound always contains the same elements in certain definite proportions. Proust: The Law of Definite Proportions

7. 7 Chapter 2 © 2013 Pearson Education, Inc. Regardless of the source, copper carbonate always has the same composition. Proust: The Law of Definite Proportions

8. 8 Chapter 2 © 2013 Pearson Education, Inc. The Berzelius experiment illustrates the Law of Definite Proportions. Proust: The Law of Definite Proportions

9. 9 Chapter 2 © 2013 Pearson Education, Inc. 1803, John Dalton Law of Multiple Proportions: Elements may combine in more than one set of proportions, with each set corresponding to a different compound. John Dalton and the Atomic Theory of Matter

10. 10 Chapter 2 © 2013 Pearson Education, Inc. John Dalton and the Atomic Theory of Matter

11. 11 Chapter 2 © 2013 Pearson Education, Inc. All matter is composed of extremely small particles called atoms. All atoms of a given element are alike and differ from the atoms of any other element. Compounds are formed when atoms of different elements combine in fixed proportions. A chemical reaction involves the rearrangement of atoms. John Dalton and the Atomic Theory of Matter

12. 12 Chapter 2 © 2013 Pearson Education, Inc. Much of John Dalton’s atomic theory has been modified. For example, John Dalton assumed that all atoms of an element are alike. He did not understand the existence of isotopes. Isotopes are atoms of the same element with different relative masses. Isotopes

13. 13 Chapter 2 © 2013 Pearson Education, Inc. 1869, Dmitri Mendeleev Mendeleev arranged the elements in order of increasing atomic mass. He left gaps for yet undiscovered elements. He also predicted the properties of those elements. When those elements were eventually discovered, many of his predictions were found to be accurate. Out of Chaos: The Periodic Table

14. 14 Chapter 2 © 2013 Pearson Education, Inc. Out of Chaos: The Periodic Table

15. 15 Chapter 2 © 2013 Pearson Education, Inc. Out of Chaos: The Periodic Table

16. 16 Chapter 2 © 2013 Pearson Education, Inc. Atoms: Real and Relevant Atoms are a very real concept. It is even possible to observe computer-enhanced images of atoms.

17. 17 Chapter 2 © 2013 Pearson Education, Inc. Leucippus Revisited: Molecules Molecules are groups of atoms chemically bonded together. A molecule of water is composed of two atoms of hydrogen (H) bonded to an atom of oxygen (O). H2OH2O