1. Atoms, Ions and the Periodic Table Chemistry 131 Chapter 2

2. Dalton’s Atomic Theory Structure of the Atom Atomic Mass Periodic Table Ions

3. Dalton’s Atomic Theory

4. Two Key Ideas led to Atomic Theory

5. Law of Conservation of Mass 1787 - Lavoisier

6. Law of Definite Proportions 1804 - Proust

7. Dalton’s Atomic Theory Published in 1808 with Four Postulates

8. All matter is composed of exceedingly small, invisible particles called Atoms.

9. Atoms of an element have a given mass and properties, atoms of differing elements differ in mass and properties.

10. Atoms are not created or destroyed in a chemical reaction.

11. Atoms combine is simple, fixed, whole-number ratios to form compounds

12. Structure of the Atom

14. Dalton perceived Atoms as the smallest unit of matter.

15. Thomson’s discovery of the electron posited a different model. Positiv e Charge Negativ e Charge Electron

16. Rutherford’s Gold Foil experiments led to yet another revision

17. The Nuclear Model of the Atom

18. Even atoms have sub- structure.

19. Hydrogen

20. Proton Mass = 1.6726×10 -24 g Charge = +1.6022×10 -19 C

22. Neutron Mass = 1.6749×10 -24 g Charge = 0

24. Electron Mass = 9.1094×10 -28 g Charge = -1.6022×10 -19 C

25. Atomic Number = Number of protons Mass Number= # Protons + # Neutrons

26. Hydrogen Also Hydrogen Isotopes

27. Ions

28. Number of Electrons = Number of Protons, if the atom is neutral.

29. Li +1 Ions

30. Atomic Mass

31. 1.6749×10 -24 g isn’t a lot

32. Atomic Mass Unit (amu)

33. 1 amu = 1/12 the mass of 1 Carbon-12 atom

34. All atomic masses are therefore relative to Carbon-12

36. The atomic masses on the periodic table are relative atomic masses

38. Relative Atomic Mass= (Isotope 1 mass × Abundance 1) + (Isotope 2 mass × Abundance 2) +…

39. Example (Silver) 107 Ag 106.9051 amu is 51.82% 109 Ag 108.9048 amu is 48.18%

40. 106.9051 amu × 0.5182 = 55.40 amu 108.9048 amu × 0.4818 = 52.47 amu 55.40 amu+52.47 amu =107.87 amu

42. Problem Given the following information, calculate the relative atomic mass of Magnesium. 24 Mg = 23.985 amu at 20.00% 25 Mg = 24.985 amu at 20.00% 26 Mg = 25.983 amu at 60.00%

43. Problem The copper mined on Earth consist of 63 Cu (62.93 amu) and 65 Cu (64.93 amu). Which isotope is more abundant? Why?

44. Periodic Table

47. Review Problems

48. Review Problem 1 How many carbon atoms are present in each sample? (a)120 amu (b)12,000 amu (c)7.22 × 10 24 amu

49. Review Problem 2 During a typical physical exam blood tests measure the cholesterol level. A high result is anything over 240.0 mg/dL. What is this in pounds/fluid ounce? If a typical human has 5.000 L of blood, how many pounds of cholesterol are present in the blood of a patient with a total cholesterol of 260.0 mg/dL?