Table of Contents

1. Table of Contents • Introduction to Atoms • Organizing the Elements • Metals • Nonmetals and Metalloids • Elements From Stardust

2. Introduction to Atoms Activities • Size of atom- Cut the paper IN HALF as many times as you can until the paper is too small to cut. Note that you will only be cutting half of the piece of paper from before in half each time. • An Analogy to Discovering Atoms Using Indirect Observations- Obtain a few ob-scertainers and listen to the BB roll around inside and determine the shape inside. Choose from the 12 shapes on the white board. Write the predicted shape and container number in your lab notebook until you have all 12.

3. Learning Objectives • Describe the structure of atoms. • Location of protons, neutrons, & electrons • Charges of protons, neutrons, & electrons • Relative mass of protons, neutrons, & electrons • Describe elements in terms of their atoms. • Explain how models are useful for studying atoms.

4. - Introduction to Atoms Models of Atoms • For over two centuries, scientists have created models of atoms in an effort to understand why matter behaves as it does. As scientists have learned more, the model of the atom has changed, since atoms are so small that they cannot be observed directly. Carbon atom

5. Atomic Theory and Models • Dalton thought that atoms were like smooth, hard spheres that could not be broken into smaller pieces.

6. Atomic Theory and Models • Thomson suggested that atoms had negatively charged electrons embedded in a positive sphere.

7. Atomic Theory and Models • Rutherford was surprised that a few particles were deflected strongly. This led him to propose an atomic model with a positively charged nucleus.

8. Atomic Theory and Models • Neils Bohr suggested that the electrons orbited around the nucleus in certain energy levels called shells. He stated that atoms absorb or give off energy when electrons move from one shell to another.

9. - Introduction to Atoms Structure of an Atom • A carbon atom (andall atoms but hydrogen atoms) consist of protons and neutrons in a nucleus that is surrounded by a cloud-like region of electrons. Carbon atom

10. All elements (and all matter) are made up of extremely small • nuclei • atoms • Large particles

11. The center of an atom is called the • protons • nucleus • neutrons • electrons

12. The nucleus of almost every atom consists of • Protons and electrons • Just neutrons • Protons and neutrons • Just protons

13. The subatomic particles that move around the nucleus quickly are called • electrons • neutrons • protons • quarks

14. Which of the following correctly describes each subatomic particle in terms of its charge? • Protons (0 or no charge), Neutrons (0 or no charge), Electrons (-) • Protons (+), Neutrons (-), Electrons (0 or no charge) • Protons (-), Neutrons (+), Electrons (0 or no charge) • Protons (+), Neutrons (0 or no charge), Electrons (-)

15. What is the overall electrical charge of an atom with 12 protons and 10 electrons • -2 • +2 • 0 • +12 • -10

16. Atoms are mostly • Protons and neutrons • Empty space • Electrons • Protons, Neutrons, & Electrons

17. Learning Objective • Describe elements in terms of their atoms. • Number of protons, neutrons, & electrons • Overall charge of the atom • Atomic mass or the Atom’s Mass Number • Atomic Number & Identity

18. Atomic Easter Egg Hunt Experiment • Goal- Determine the number of protons (atomic number), number of neutrons, atomic mass, and identity of the nucleus of 5 different atoms for 5 different elements. • Background (Periodic Table on page 84 and 85 in your textbook): • Orange BB’s = protons and Green BB’s = neutrons • Number of protons + number of neutrons = atomic mass (because protons and neutrons are 1 mass unit each). • Number of protons = atomic number (found above the element’s symbol in the center for the table in your book).

19. - Introduction to Atoms Atoms, Elements, & Isotopes • Atomic Number determines the identity which equals the number of protons. The number of neutrons + the number of protonsequalsthe mass number because each have a mass of 1 atomic mass unit. • Atoms of all isotopes of carbon contain six protons, but they differ in the number of neutrons. • Carbon-12 is the most common form of carbon, where the 12 is the mass number. Examine the symbols below.(6 = atomic number = # of protons; 12, 13, and 14 = atomic mass = # of protons + # of neutrons). • Notice that all of the isotopes (and atoms) are neutral(same # of protons and electrons).

20. Atoms & Elements Flow Chart • He-4 Identity Atomic Mass Find on Periodic Table Mass = # of protons + # of neutrons (both 1 mass unit each) Find Atomic number above symbol Atomic Mass MINUS the # of protons = # of neutrons Atomic Number = # of protons # of electrons = # of protons for neutral atoms

21. Practice Problems • For a neutral Ne-22 atom, determine the… • Identity • Atomic Mass • Atomic Number • # of p+ • # of n0 • # of e- • For a neutralF-19 atom, determine a-f from above.

22. The atomic number of an element is the same as the • Number of protons & neutrons in the nucleus of that atom. • Number of protons in the nucleus of that atom. • Number of neutrons in the nucleus of that atom. • Number of electrons in the nucleus of that atom.

23. The atomic number determines the __________ of an atom. • identity • mass • Number of neutrons • Number of subatomic particles

24. Protons and neutrons are both • 2 atomic mass units each. • 0 atomic mass units each. • 1 atomic mass unit each. • 0.5 atomic mass units each.

25. What 2 subatomic particles make up most of the mass of an atom? • Protons and neutrons. • Protons and electrons. • Just neutrons. • Neutrons and electrons.

26. For a Nitrogen-14 atom, what does the 14 represent? • Atomic number of proton number • Mass number or atomic mass • Atomic particle number • The atom’s identity

27. Determine the number of protons for a hydrogen-3 atom. • 1 • 2 • 3 • 0

28. Determine the number of neutrons for a hydrogen-3 atom. • 1 • 2 • 3 • 0

29. Determine the number of electrons for a neutral hydrogen-3 atom. Provide the overall charge of the atom too. • 1 electron; No charge • 1 electron; -1 • 2 electrons; -1 • 3 electrons; No charge • 1 electron; +1

30. Practice Problems • Determine the atomic number and the atomic mass for an atom that has 8 protons and 8 neutrons. • What is the identity of this atom? • Suppose an atom has 6 protons and 8 neutrons, what is the atomic number and the identity of this atom? • What is the name given to the type of atom in the question above and WHY? Hint: Look at the number of protons and neutrons and think about the term for these types of atoms we covered yesterday. • Chlorine-37 is an isotope of chlorine. How many protons, neutrons, and electrons does it have? • What is Chlorine-37's atomic number? • Potassium-40 is a radioactive isotope of potassium (a very small amount can be found in bananas but it doesn’t harm you). How many protons, neutrons, and electrons does potassium-40 have? • What is Potassium-40’s atomic number?

31. Practice Problem Answers • 8 (Atomic Number), 16 (Atomic Mass) • Oxygen-16 • 6 (Atomic Number), Carbon-14 • Isotope- Same # of protons, but a different number of neutrons • Chlorine-37: 17 protons (Atomic #), 20 neutrons (Mass – Atomic #), 17 electrons (Same as # of protons b/c it’s neutral) • Chlorine-37: Atomic Number = 17 • Potassium-40: 19 protons (Atomic #), 21 neutrons (Mass - # of protons), 19 electrons (same as # of protons b/c it’s neutral) • K-40: Atomic Number = 19

32. Noggin Knockers Quiz (13 points- 1 pt. per part) • Isotopes • a-f (center) and 3. a-f (bottom right) • Potassium • 19 • 19 • 19 • 39 • 20 • Oxygen • 8 • 8 • 8 • 18 • 10

33. Learning Objectives • Explain how Mendeleev discovered the pattern that led to the periodic table. • Describe the data about elements that are found in the periodic table. • Describe how the organization of the periodic table is used to predict the properties of elements.

34. - Organizing the Elements Finding Data on Elements • Each square of the periodic table includes an element’s atomic number, chemical symbol, name, and average atomic mass. The atomic mass contains a decimal because it is an average of all of the isotopes that occur in the real world. • Rounding the average atomic mass will almost alwaysgive you the mass of the most common isotope of that element. Average

35. By examining the element block for Magnesium on p. 84 & 85, what is the elemental symbol for Magnesium? • Ca • M • Mg • Na

36. By examining the element block for Magnesium on p. 84 & 85, what is its atomic number? • 24.305 • 12 • 2 • 3

37. By examining the element block for Magnesium on p. 84 & 85, what is the average atomic mass for Magnesium? • 12 • 2 • 24.305 • 3

38. By examining the element block for Magnesium (Mg) on p. 84 & 85, what is the main reason why magnesium’s atomic mass is NOT a whole number? • b/c protons and neutrons don’t weight exactly 1 mass unit each. • b/c it’s the number of protons + the number of neutrons. • b/c it doesn’t include the mass of the electrons. • b/c it’s a weighted average of the isotopes that occur naturally.

39. What’s probably the most common isotope of Neon (#10)? • Neon-10 • Neon-20.179 • Neon-20 • N-10

40. What’s probably the most common isotope of Argon (#18)? • Argon-36 • Argon-38 • Argon-39 • Argon-40

41. Noggin Knockers/Hwk. Grade (12 points) • 1 (3 points)- protons (+), neutrons (0 or neutral), electrons (-) • 2 (2 points)- b/c there is an equal number of positive charges (protons) and negative charges (electrons) • 3 N-15: (6 points)- • (a) Nitrogen • (b) Atomic # = 7 • (c) 7 protons • (d) 7 electrons (same as # of protons, overall charge = 0) • (e) Mass = 15 amu • (f) 8 neutrons (Mass - # of protons = 15-7 = 8), • 4 (1 point)- Atoms are too small to see even with a powerful microscope

42. Learning Objectives • Explain how Mendeleev discovered the pattern that led to the periodic table. • Describe the data about elements that are found in the periodic table. • Describe how the organization of the periodic table is used to predict the properties of elements.

43. Chemical Properties of Some Elements Data Table • Goal: (Use the title to determine the goal) • Conclusions (Periodic Table Trends) • Examine the columns in the periodic table that contain the elements to the right and your observations from the experiment. • Elements in the same group or column have ____________ properties. (Similar or different) • As you go _________ (direction- use your observations for magnesium and calcium along with their locations on the periodic table) and to the ___________ (different direction- use the sodium demo & its location on the periodic table), the elements become more reactive. • After watching the reaction videos… • Vice versa, as you go _________ (direction) and way over to the ___________ (different direction), the elements also are more reactive (not counting the column or group all the way to the right).

44. - Organizing the Elements Organization of the Periodic Table • Elements in a column or group also typically have similar properties. • Examples- Sodium and Lithium reacting with water. Chlorine and bromine gases are both harmful to your lungs. • The 18 columns of the periodic table reflect a repeating pattern of properties that generally occur across a period.

45. Mendeleev & the Periodic Table • Mendeleev originally noticed a repeating pattern of properties (both chemical and physical) when he placed the elements in order of atomic mass, unlike today’s periodic table. • How is today’s periodic table arranged? • By atomic number (same as the number of protons)

46. - Metals Melting Points in a Group of Elements • The properties of elements within a single group in the periodic table often vary in a certain pattern. The following graph shows the melting points of Group 1 elements (alkali metals) from lithium to francium.

47. - Metals Metals in the Periodic Table • The metals in Group 1, from lithium to francium, are the most reactive metals and are called the alkali metals. Alkali metals react with atoms of other elements by losing one electron.

48. - Metals Metals in the Periodic Table • Group 2 of the periodic table contains the alkaline earth metals. These elements are not as reactive as the metals in Group 1, but they are more reactive than most other metals.

49. - Metals Metals in the Periodic Table • The transition metals are less reactive than the metals in Groups 1 and 2. All metals are typically shiny, malleable (can be hammered into flat sheets), ductile (made into a long wire), and can conduct electricity. • Also, thereactivity of metals decreases as you go across a row in the periodic table.

50. - Metals Metals in the Periodic Table • Only some of the elements in Groups 13 through 15 of the periodic table are metals. These metals are not nearly as reactive as those on the left side of the table.