2. Chapter Menu Chapter Introduction Lesson 1Lesson 1Electrons and Energy Levels Lesson 2Lesson 2Compounds, Chemical Formulas, and Covalent Bonds Lesson 3Lesson 3Ionic and Metallic Bonds Chapter Wrap-Up

3. Chapter Introduction How do elements join together to form chemical bonds?

4. Lesson 1 Reading Guide - Vocab chemical bond valence electron electron dot diagram Electrons and Energy Levels

5. Lesson 1-1 Elements on the periodic table are organized in periods (rows) and groups (columns). The periodic table lists elements in order of atomic number, which increases from left to right as you move across a period. The Periodic Table

6. Lesson 1-1 The three main regions of elements on the periodic table classify elements as metals, nonmetals, or metalloids.

7. Lesson 1-1 The Periodic Table (cont.) Except for hydrogen, elements on the left side of the table are metals. Nonmetals are on the right side of the table. Metalloids form the narrow stair-step region between metals and nonmetals.

8. Lesson 1-2 A chemical bond is *chemical bond Atoms contain protons, neutrons, and electrons. Each proton has a positive charge; each neutron has no charge; and each electron has a negative charge. Atoms Bond

9. Lesson 1-2 Protons and neutrons are *

10. Lesson 1-2 The atomic number of an element is the number of protons in each atom of that element. An electron moves around the nucleus at a * Atoms Bond (cont.)

11. Lesson 1-2 Areas of space in which electrons move around the nucleus are called energy levels. Electrons closest to the nucleus have the *. Atoms Bond (cont.)

12. Lesson 1-2 Electron Energy Levels

13. Lesson 1-2 Atoms Bond (cont.) How is an electron’s energy related to its position in an atom?

14. Lesson 1-2 The attraction between the positive nucleus of one atom and the negative electrons of another atom is what creates a chemical bond. A valence electron is *valence electron Atoms Bond (cont.)

15. Lesson 1-2 The number of valence electrons in each atom of an element can help determine the type and number of bonds that an atom can form. Atoms Bond (cont.) valence from Latin valentia, means “strength, capacity”

16. Lesson 1-2 The periodic table can tell you how many valence electrons an atom has.

17. Lesson 1-2 In 1916 an American chemist named Gilbert Lewis developed the electron dot diagram, a model that represents *electron dot diagram Atoms Bond (cont.)

18. Lesson 1-3

19. Lesson 1-2 Atoms with eight valence electrons are chemically stable and do not easily react with other atoms. Atoms that have between one and seven valence electrons are reactive or chemically unstable and easily bond with other atoms to form chemically stable compounds. Atoms Bond (cont.)

20. Lesson 1-2 The elements in group 18 are called noble gases. With the exception of helium, noble gases have eight valence electrons and are chemically stable. Atoms Bond (cont.)

21. Lesson 1-2 Atoms gain, lose, or share valence electrons and become chemically stable.

22. Lesson 1-2 Atoms Bond (cont.) Why do atoms gain, lose, or share electrons?

23. Lesson 1 - VS Electrons are less strongly attracted to a nucleus the farther they are from it, similar to the way a magnet attracts a paper clip.

24. Lesson 1 - VS Electrons in atoms are in energy levels around the nucleus. Valence electrons are involved in chemical bonding.

25. Lesson 1 - VS All noble gases, except He, have four pairs of dots in their electron dot diagrams. Noble gases are chemically stable.

26. Lesson 1 - Now 1.Elements rarely exist in pure form. Instead, combinations of elements make up most of the matter around you. 2.Chemical bonds that form between atoms involve electrons. Do you agree or disagree?

27. Lesson 2 Reading Guide - KC How do elements differ from the compounds they form? What are some common properties of a covalent compound? Why is water a polar compound? Compounds, Chemical Formulas, and Covalent Bonds

28. Lesson 2 Reading Guide - Vocab covalent bond molecule polar molecule chemical formula Compounds, Chemical Formulas, and Covalent Bonds

29. Lesson 2-1 Compounds are chemical combinations of different types of atoms. Chemical bonds join atoms together. From Elements to Compounds

30. Lesson 2-1 From Elements to Compounds (cont.) bond Science Use a force that holds atoms together in a compound Common Use a close personal relationship between two people

31. Lesson 2-1 From Elements to Compounds (cont.) How is a compound different from the elements that make it up?

32. Lesson 2-2 A covalent bond is a *.covalent bond A compound formed from many covalent bonds is called a covalent compound. Covalent Bonds—Electron Sharing

33. Lesson 2-2 Atoms with less than eight valence electrons become chemically stable by forming a chemical bond.

34. Lesson 2-2 A single covalent bond exists when two atoms share one pair of valence electrons. A double covalent bond exists when two atoms share two pairs of valence electrons A triple covalent bond exists when two atoms share three pairs of valence electrons. Covalent Bonds—Electron Sharing (cont.)

35. Lesson 2-2 The more valence electrons that two atoms share, the stronger the covalent bond is between the atoms.

36. Lesson 2-3 When two or more atoms share valence electrons, they form a stable covalent compound. Covalent compounds usually have* They are usually * Covalent compounds are * Covalent Compounds

37. Lesson 2-3 Covalent Compounds (cont.) What are some common properties of covalent compounds?

38. Lesson 2-3 A molecule is a *.molecule * is a polar molecule.polar molecule Covalent Compounds (cont.)

39. Lesson 2-3 Covalent Compounds (cont.) polar from Latin polus, means “pole”

40. Lesson 2-4 Atoms of a polar molecule share their valence electrons unequally.

41. Lesson 2-4 Atoms of a nonpolar molecule share their valence electrons equally.

42. Lesson 2-4 Covalent Compounds (cont.) Why is water a polar compound?

43. Lesson 2-3 A chemical formula is a group of chemical symbols and numbers that *chemical formula A chemical formula describes the types of atoms in a compound or a molecule, but it does not explain the shape or appearance of the molecule. Covalent Compounds (cont.)

44. Lesson 2-4 Chemical formulas and molecular models provide information about molecules.

45. Lesson 2 - VS A chemical formula is one way to show the elements that make up a compound.

46. Lesson 2 - VS A covalent bond forms when atoms share valence electrons. The smallest particle of a covalent compound is a molecule.

47. Lesson 2 - VS Water is a polar molecule because the oxygen and hydrogen atoms unequally share electrons.

48. Lesson 3 Reading Guide - KC What is an ionic compound? How do metallic bonds differ from covalent and ionic bonds? Ionic and Metallic Bonds

49. Lesson 3 Reading Guide - Vocab ion ionic bond metallic bond Ionic and Metallic Bonds

50. Lesson 3-1 An ion is an atom that is *ion Understanding Ions ion from Greek ienai, means “to go”

51. Lesson 3-1 Because electrons have a negative charge, losing or gaining an electron changes the overall charge of an atom. Atoms that lose valence electrons become ions with a positive charge. Metal atoms, such as sodium, become more stable when they lose valence electrons and form a chemical bond with a nonmetal. Understanding Ions (cont.)

52. Lesson 3-1 Sodium atoms have a tendency to lose a valence electron. Chlorine atoms have a tendency to gain a valence electron.

53. Lesson 3-1 Atoms are electrically neutral because they have the same number of protons and electrons. Once an atom gains or loses electrons, it becomes a charged ion. Understanding Ions (cont.)

54. Lesson 3-2 When forming a compound, the nonmetal atoms gain the electrons lost by the metal atoms. * is an ionic bond.ionic bond Ionic Bonds—Electron Transferring

55. Lesson 3-2 An ionic bond forms between Na and Cl when an Na atom transfers an electron to a Cl atom.

56. Lesson 3-2 Ionic Bonds—Electron Transferring (cont.) What holds ionic compounds together?

57. Lesson 3-3 Individual ions in an ionic compound are strongly attracted to each other. Covalent compounds are made up of many molecules. When nonmetal ions bond to metal ions in an ionic compound there is a large collection of oppositely charged ions and no molecules. Ionic Compounds

58. Lesson 3-4 A metallic bond is a bond formed when *metallic bond Valence electrons in metals are not bonded to one atom. Instead, a “sea of electrons” surrounds the positive ions. Metallic Bonds—Electron Pooling

59. Lesson 3-4 Valence electrons are free to move among all the aluminum (Al) ions.

60. Lesson 3-4 Metallic Bonds—Electron Pooling (cont.) How do metal atoms bond with one another?

61. Lesson 3-4 Metals are * Metallic Bonds—Electron Pooling (cont.)

62. Lesson 3-4

64. Lesson 3 - VS Metal atoms lose electrons and nonmetal atoms gain electrons and form stable compounds. An atom that has gained or lost an electron is an ion.

65. Lesson 3 - VS An ionic bond forms between positively and negatively charged ions.

66. Lesson 3 - VS A metallic bond forms when many metal atoms share their pooled valence electrons.