1. The Atom CHAPTER 3.1 MS. COX’S CHEMISTRY CLASS

2. Lesson Objectives Explain the law of conservation of mass, the law of multiple proportions and the law of definite proportions. (These are the “Fundamental Laws”) Summarize the 5 points of Dalton’s Atomic Theory Explain the relationship between Dalton’s Atomic Theory and the law of conservation of mass, law of multiple proportions and law of definite proportions.

3. The Fundamental Laws

4. Law of Conservation of Mass Definition Review: A Chemical Reaction is the transformation of one or more substance(s) into one or more new substance(s). One step further… Law of Conservation of mass states that during normal chemical reactions mass is not created or destroyed it just changes form.

5. Law of Conservation of Mass

6. Law of Definite Proportions Law of Definite Proportions states that a specific compound contains the same elements in the exact same proportion regardless of the sample size. What does this mean? For Example: This means that H 2 O is ALWAYS 2 Hydrogens and 1 oxygen regardless of if we have 1 drop of water or an ocean full of water.

7. Law of Multiple Proportions

8. The Math Behind Multiple Proportions

9. Dalton’s Atomic Theory 1.All matter is composed of extremely small particles called atoms. 2.Atoms of a given element are identical in size, mass, and other properties. (atoms of different elements differ in size, mass, and other properties.) 3.Atoms cannot be subdivided, created, or destroyed (They are the smallest unit of matter) 4.Atoms of different elements combine in simple whole-number ratios to form chemical compounds. (Laws of Definite and Multiple Proportions) 5.In chemical reactions, atoms are combined, separated, or rearranged. (Law of Conservation of Mass)

10. Dalton was wrong on a few key points Dalton said: “Atoms of a given element are identical in size, mass, and other properties.” Dalton did not account for Isotopes. Isotopes are atoms that have different masses. For example U-239 and U-235. (We’ll talk about Isotopes more next time) Dalton said: “Atoms cannot be subdivided” (They are the smallest unit) We now know that Atoms are made up of protons, neutrons, electrons. (Again we’ll talk more about this next time)

11. Dalton did get some stuff right! Modern Atomic Theory still states that 1.All matter is composed of atoms 2.Atoms of any one element differ in properties from atoms of another element. 3.Atoms cannot be created or destroyed in typical chemical reactions.

12. Lesson Objectives Explain the law of conservation of mass, the law of multiple proportions and the law of definite proportions. (These are the “Fundamental Laws”) Summarize the 5 points of Dalton’s Atomic Theory Compare Dalton’s Theory to Modern Atomic Theory Explain the relationship between Dalton’s Atomic Theory and the law of conservation of mass, law of multiple proportions and law of definite proportions.