Atoms: The Building Blocks of Matter

1. Atoms: The Building Blocks of Matter Unit 2

2. Introduction to the Atom • Modern Atomic Theory • Subatomic Particles • Isotopes • Ions • Essential Standards and objectives: • 1.1.1 Analyze the structure of atoms, isotopes, and ions. • 1.1.2 Analyze an atom in terms of the location of electrons. • 1.1.3Explain the emission of electromagnetic radiation in spectral form in terms • of the Bohr model. • 1.1.4 Explain the process of radioactive decay using nuclear equations and half-life. • 2.2.5 Analyze quantitatively the composition of a substance. (Introduction to moles)

3. The Atom: Smallest particle of an element that retains the chemical properties of the element. Essential Questions: What is an atom? What is its structure? What determines properties of an element?

4. Atoms act in orderly, predictable ways.

5. PHET Build an Atom • Use this in the search window • Share a computer with a partner • Individual work (write your answers on a separate paper) • http://phet.colorado.edu/en/simulation/build-an-atom

6. Explain: How does this graphic demonstrate the characteristics of an atom? Make sure that you include each graphic (portions) in your explanation

7. Reading: Cornell notes Essential questions: What are the characteristics of an atom? In your notes: address both individual atoms and atoms of an element

8. Modern Atomic Theory • All matter: • Atoms of a given element: • Atoms cannot be created nor destroyed in: • In chemical reactions, atoms are

9. Atomic Theory (cont.) • To form compounds: Law of Definite Proportions Law of Multiple Proportions

10. Summary Table: Atomic Structure- Subatomic Particles SubatomicLocationChargeMassImportance ParticleAMU

11. Designation of Atomic Structure • Atomic number (Z): • On the Periodic Table: • Mass number (A): • On the Periodic Table:

12. Representing atoms • Information from symbols and the Periodic Table

13. What does this symbol tell us? Protons: Neutrons: Electrons:

14. 20 Ca 40.08 Designations for the Atomic Structure Atomic number (Z): • On the Symbol • On the Periodic Table Mass number (A): • On the Symbol • On the Periodic Table

15. Review: What is Z? What is A? Determine the number of protons, neutrons, and electrons. 31 Ga Gallium 69.72 32 Ge Germanium 72.61

17. Periodic Table: an Important Tool in Chemistry but no set rules for what is included and where 16 S 32.06 S 16 32.06 How can we tell which is the atomic number and the mass number?

18. AMU = relative measurement and used for comparison Atomic Mass Unit AMU The “amu” is defined as one twelfth of the mass of an atom of carbon-12  (with 6 protons and 6 neutrons) and has a value of 1.660538921×10−27kg.

19. Organization of the Periodic Table • Columns – Groups • All the elements have similar chemical and physical properties • All will chemically react in a similar way • Names of groups • Rows – Periods • Elements have same number of energy levels

20. Isotopes

21. Isotopes

22. Isotopes: • Atoms of an element with different masses • Naturally occurring • Some are stable and some are radioactive (unstable) • Isotopes of an element have the same number of ___________ and a different number of ______________.

23. Identifying Isotopes • Isotope Notation 1. 2. On the Periodic Table, the number with the Decimal point is:

24. Atoms of the Same Element

25. Atoms of the Same Element

26. Atoms of the Same Element

27. Atomic Mass • Weighted Average Mass of isotopes • Based on the percentage of each isotope present.

28. Grades are often computed using a weighted average. • Suppose that homework counts 10%, quizzes 20%, Labs 10% and tests 60%. • If: homework grade is 92 quiz grade is 68 lab grade is 88 test grade is 81 What’s the overall grade?

29. Practice • Atomic Structure • Identify the number of proton, neutron, & electrons of an atom of a specific element • Rounding the atomic mass on the Periodic Table gives the mass of the most common isotope • Atomic Number & Isotopes • Correct symbol: A & Z • Complete the table • Complete the questions.

30. Practice: • Find the Average Atomic Mass • Nucleus of each atom is represented • Graphic below #4 - explains #5-7 • Isotopes: Atomic Number & Mass Number • Determine based on the chart – not the PT • 2 Isotope notations • Element – A (X-A) A ZX

31. Find Average Atomic Mass

32. Atomic Number & Isotope

33. Isotopes: Atomic Number & Mass Number

34. What is the atomic mass of Nitrogen given: • N-14 is 99.64% of all nitrogen • N-15 is 0.36% of all nitrogen

35. What is the atomic mass of Indium if: • In-113 is 4.24% • In-115 is 95.72%

36. Calculate % Abundances from Masses • Requires the use of 2 equations and 2 unknowns. • Isotope 1(X) + Isotope 2(Y) = Atomic Mass • X + Y = 1 • Substitute and solve for X or Y!

37. What are the percent abundances of Vanadium if • V-50 + V-51 = 50.94 amu

38. What are the percent abundances for Gallium if: • Ga-69 + Ga-71 = 69.72

39. Atom: Scanning Tunneling Microscope

40. Study of atomic particles

41. Scanning Tunneling Microscrope

42. Development of the Atomic Theory • Essential Question: Why do elements have different properties?

43. Here are several models of the atom as they were developed in history: ............ ...... ................ Development of the Modern Atomic Model

44. Ancient Question

45. Atomic investigation

46. Bohr

47. Quantum Model • Electron Cloud model of the atom

48. Representing atoms with the Bohr model

49. Representing atoms with the Bohr Model

50. Bohr Model – Simplified but Useful Model P1 P2 P3