1. WHY DO ATOMS BOND TOGETHER? ATOMS WANT TO ACHIEVE A STABLE ELECTRON CONFIGURATION (OR FULL OUTER SHELL OF VALENCE ELECTRONS).

2. WHY DO ATOMS BOND TOGETHER? ATOMS WANT TO ACHIEVE A STABLE ELECTRON CONFIGURATION (OR FULL OUTER SHELL OF VALENCE ELECTRONS). An atom’s reactivity (or ability to bond with other atoms) is based on its valence electrons.

3. WHY DO ATOMS BOND TOGETHER? ATOMS WANT TO ACHIEVE A STABLE ELECTRON CONFIGURATION (OR FULL OUTER SHELL OF VALENCE ELECTRONS). An atom’s reactivity (or ability to bond with other atoms) is based on its valence electrons. Every atom wants to fill its outer shell (or highest occupied energy level) with valence electrons.

4. WHY DO ATOMS BOND TOGETHER? ATOMS WANT TO ACHIEVE A STABLE ELECTRON CONFIGURATION (OR FULL OUTER SHELL OF VALENCE ELECTRONS). An atom’s reactivity (or ability to bond with other atoms) is based on its valence electrons. Every atom wants to fill its outer shell (or highest occupied energy level) with valence electrons. Atoms can fill their shells by bonding with other atoms.

5. WHY DO ATOMS BOND TOGETHER? ATOMS WANT TO ACHIEVE A STABLE ELECTRON CONFIGURATION (OR FULL OUTER SHELL OF VALENCE ELECTRONS). An atom’s reactivity (or ability to bond with other atoms) is based on its valence electrons. Every atom wants to fill its outer shell (or highest occupied energy level) with valence electrons. Atoms can fill their shells by bonding with other atoms. Once this shell is filled, the atom is stable and not likely to react with other atoms.

6. WHY DO ATOMS BOND TOGETHER? HOW DO WE SHOW THE VALENCE ELECTRONS?

8. WHY DO ATOMS BOND TOGETHER? HOW DO WE SHOW THE VALENCE ELECTRONS? The electrons in the outer shell are called valence electrons.

9. WHY DO ATOMS BOND TOGETHER? HOW DO WE SHOW THE VALENCE ELECTRONS? The electrons in the outer shell are called valence electrons. Electron dot diagrams show the valence electrons.

10. WHY DO ATOMS BOND TOGETHER? HOW DO WE SHOW THE VALENCE ELECTRONS? The electrons in the outer shell are called valence electrons. Electron dot diagrams show the valence electrons. Each dot represents one valence electron. Draw the symbol for an element then put the necessary number of dots around it.

12. WHAT ARE THE TYPES OF BONDS? IONIC BOND Sometimes atoms transfer electrons with each other to fill their outer shells and achieve stability. When electrons are transferred, an ionic bond is formed.

13. WHAT ARE THE TYPES OF BONDS? IONIC BOND Sometimes atoms transfer electrons to each other to fill their outer shells and achieve stability. When electrons are transferred, an ionic bond is formed. In an ionic bond, some atoms give up or lose their valence electrons – Groups 1A, 2A and 3A.

14. WHAT ARE THE TYPES OF BONDS? IONIC BOND Sometimes atoms transfer electrons with each other to fill their outer shells and achieve stability. When electrons are transferred, an ionic bond is formed. In an ionic bond, some atoms give up or lose their valence electrons – Groups 1A, 2A and 3A. Other atoms take or gain an electron – Groups 5A, 6A and 7A.

15. WHAT ARE THE TYPES OF BONDS? IONIC BOND Sometimes atoms transfer electrons with each other to fill their outer shells and achieve stability. When electrons are transferred, an ionic bond is formed. In an ionic bond, some atoms give up or lose their valence electrons – Groups 1A, 2A and 3A. Other atoms take or gain an electron – Groups 5A, 6A and 7A. Each atom ends up with a full shell and is more stable.

17. WHAT ARE THE TYPES OF BONDS? FORMATION OF IONS When an atom gains or loses electrons, the number of electrons does not match the number of protons.

18. WHAT ARE THE TYPES OF BONDS? FORMATION OF IONS When an atom gains or loses electrons, the number of electrons does not match the number of protons. Positive and negative charges are no longer balanced.

19. WHAT ARE THE TYPES OF BONDS? FORMATION OF IONS When an atom gains or loses electrons, the number of electrons does not match the number of protons. Positive and negative charges are no longer balanced.

20. WHAT ARE THE TYPES OF BONDS? FORMATION OF IONS When an atom gains or loses electrons, the number of electrons does not match the number of protons. Positive and negative charges are no longer balanced. The atom then has either a positive or negative charge and is called an ion.

21. WHAT ARE THE TYPES OF BONDS? FORMATION OF IONS When an atom gains or loses electrons, the number of electrons does not match the number of protons. Positive and negative charges are no longer balanced. The atom then has either a positive or negative charge and is called an ion. If atom gains electrons, then it has a negative charge. Negative ions are called anions.

22. WHAT ARE THE TYPES OF BONDS? FORMATION OF IONS When an atom gains or loses electrons, the number of electrons does not match the number of protons. Positive and negative charges are no longer balanced. The atom then has either a positive or negative charge and is called an ion. If atom gains electrons, then it has a negative charge. Negative ions are called anions. If atom loses electrons, then it has a positive charge. Positive ions are called cations.

24. WHAT ARE THE TYPES OF BONDS? IONIZATION ENERGY Energy is needed for an electron to leave an atom, more energy than needed to move up an energy level.

25. WHAT ARE THE TYPES OF BONDS? IONIZATION ENERGY Energy is needed for an electron to leave an atom, more energy than needed to move up an energy level. The amount of energy needed is called ionization energy.

26. WHAT ARE THE TYPES OF BONDS? IONIZATION ENERGY Energy is needed for an electron to leave an atom, more energy than needed to move up an energy level. The amount of energy needed is called ionization energy. Ionization energies increase as you move left to right on the periodic table, and from bottom to top.

27. WHAT ARE THE TYPES OF BONDS? IONIZATION ENERGY Energy is needed for an electron to leave an atom, more energy than needed to move up an energy level. The amount of energy needed is called ionization energy. Ionization energies increase as you move left to right on the periodic table, and from bottom to top. It takes more energy to move an electron from a nonmetal than from a metal.

28. WHAT ARE THE TYPES OF BONDS? IONIZATION ENERGY Energy is needed for an electron to leave an atom, more energy than needed to move up an energy level. The amount of energy needed to remove an electron is called ionization energy. Ionization energies increase as you move left to right on the periodic table, and from bottom to top. It takes more energy to move an electron from a nonmetal than from a metal. Because of their differences in ionization energies, ionic bonds are most often formed between a metal and a nonmetal.

29. WHAT ARE THE TYPES OF BONDS? IONIC COMPOUNDS When ionic bonds are created, ionic compounds are formed.

30. WHAT ARE THE TYPES OF BONDS? IONIC COMPOUNDS When ionic bonds are created, ionic compounds are formed. The positive and negative charges of the ions must balance or be equal to zero.

31. WHAT ARE THE TYPES OF BONDS? IONIC COMPOUNDS When ionic bonds are created, ionic compounds are formed. The positive and negative charges of the ions must balance or be equal to zero. The strong attraction between the positive and negative ions gives ionic compounds certain properties: solid high melting point brittle forms crystals

32. WHAT ARE THE TYPES OF BONDS? CRYSTALS The attraction between negative and positive ions also creates a lattice or framework for ionic compounds to form crystals.

33. WHAT ARE THE TYPES OF BONDS? CRYSTALS The attraction between negative and positive ions also creates a lattice or framework for ionic compounds to form crystals. The shape of a crystal depends on the ratio of positive and negative ions and the relative sizes of the ions.

35. WHAT ARE THE TYPES OF BONDS? COVALENT BOND Sometimes ionization energy is too high for atoms to lose or transfer electrons.

36. WHAT ARE THE TYPES OF BONDS? COVALENT BOND Sometimes ionization energy is too high for atoms to lose or transfer electrons. Instead, nonmetals with high ionization energies share valence electrons to form a bond.

37. WHAT ARE THE TYPES OF BONDS? COVALENT BOND Sometimes ionization energy is too high for atoms to lose or transfer electrons. Instead, nonmetals with high ionization energies share valence electrons to form a bond. The attraction between the shared electrons and the protons in each nucleus holds the atoms together.

38. WHAT ARE THE TYPES OF BONDS? COVALENT BOND Sometimes ionization energy is too high for atoms to lose or transfer electrons. Instead, nonmetals with high ionization energies share valence electrons to form a bond. The attraction between the shared electrons and the protons in each nucleus holds the atoms together. Covalent bonds are not as strong as ionic bonds.

39. WHAT ARE THE TYPES OF BONDS? COVALENT BOND Sometimes ionization energy is too high for atoms to lose or transfer electrons. Instead, nonmetals with high ionization energies share valence electrons to form a bond. The attraction between the shared electrons and the protons in each nucleus hold the atoms together. Covalent bonds are not as strong as ionic bonds. Covalent bonds form molecules. Each atom must share an electron in a covalent bond.

40. - Covalent Bonds How Covalent Bonds Form The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons.

41. - Covalent Bonds How Covalent Bonds Form The oxygen atom in water and the nitrogen atom in ammonia are each surrounded by eight electrons as a result of sharing electrons with hydrogen atoms.

42. - Covalent Bonds How Covalent Bonds Form An oxygen molecule contains one double bond, while a carbon dioxide molecule has two double bonds. A nitrogen molecule contains one triple bond.

43. WHAT ARE THE TYPES OF BONDS? MOLECULES OF ELEMENTS Two atoms of the same nonmetal often join together and share electrons in a covalent bond. This is called a diatomic molecule. Examples: H 2, O 2, N 2.

44. WHAT ARE THE TYPES OF BONDS? MOLECULES OF ELEMENTS Two atoms of the same nonmetal often join together and share electrons in a covalent bond. This is called a diatomic molecule. Examples: H 2, O 2, N 2. Sometimes they share more than one electron to get full shells. Sharing two electrons makes a double bond, sharing three electrons makes a triple bond.

45. WHAT ARE THE TYPES OF BONDS? UNEQUAL SHARING OF ELECTRONS Atoms on the top of and to the right of the periodic table have a greater attraction for electrons.

46. WHAT ARE THE TYPES OF BONDS? UNEQUAL SHARING OF ELECTRONS Atoms on the top of and to the right of the periodic table have a greater attraction for electrons. Electrons spend more time around these atoms, and so it has a small negative charge, creating a polar covalent bond.

47. WHAT ARE THE TYPES OF BONDS? UNEQUAL SHARING OF ELECTRONS Atoms on the top of and to the right of the periodic table have a greater attraction for electrons. Electrons spend more time around these atoms, and so it has a small negative charge, creating a polar covalent bond. Polar molecules – two atoms with a polar covalent bond will form a polar molecule, one side positive and one side negative.

48. WHAT ARE THE TYPES OF BONDS? UNEQUAL SHARING OF ELECTRONS Atoms on the top of and to the right of the periodic table have a greater attraction for electrons. Electrons spend more time around these atoms, and so it has a small negative charge, creating a polar covalent bond. Polar molecules – two atoms with a polar covalent bond will form a polar molecule, one side positive and one side negative. Three or more atoms joined by covalent bonds do not always form a polar molecule, it depends on the shape.

49. WHAT ARE THE TYPES OF BONDS? UNEQUAL SHARING OF ELECTRONS Atoms on the top of and to the right of the periodic table have a greater attraction for electrons. Electrons spend more time around these atoms, and so it has a small negative charge, creating a polar covalent bond. Polar molecules – two atoms with a polar covalent bond will form a polar molecule, one side positive and one side negative. Three or more atoms joined by covalent bonds do not always form a polar molecule, it depends on the shape. Because polar molecules have a positive and negative side, they are attracted to each other more than other molecules.

50. WHAT ARE THE TYPES OF BONDS? UNEQUAL SHARING OF ELECTRONS Water is a polar molecule – the oxygen side has a slight negative charge. This is why water has special properties: Dissolves substances, absorbs and retains heat, cohesion, adhesion, capillary action.

51. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS Metals tend to give up their electrons to get a stable electron configuration. But what if there are no nonmetals around to take their electrons? Metals can lose their electrons (at least temporarily) by sharing electrons with other metal atoms.

52. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS Metals tend to give up their electrons to get a stable electron configuration. But what if there are no nonmetals around to take their electrons? Metals can lose their electrons (at least temporarily) by sharing electrons with other metal atoms. This sharing of electrons and the attraction between the positive nuclei of the metal atoms and the shared electrons forms a metallic bond.

53. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS Metals tend to give up their electrons to get a stable electron configuration. But what if there are no nonmetals around to take their electrons? Metals can lose their electrons (at least temporarily) by sharing electrons with other metal atoms. This sharing of electrons and the attraction between the positive nuclei of the metal atoms and the shared electrons forms a metallic bond. Metallic bonds give metals their special properties.

54. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS HOW DOES THIS WORK? Metals share all of their electrons in a “sea of electrons”. Electrons float around and are not in any shell.

55. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS HOW DOES THIS WORK? Metals share all of their electrons in a “sea of electrons”. Electrons float around and are not in any shell. The positive nucleus of each metal atom becomes a cation. The attraction of these cations to the electrons bonds the atoms together in a lattice or framework.

56. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS HOW DOES THIS WORK? Metals share all of their electrons in a “sea of electrons”. Electrons float around and are not in any shell. The positive nucleus of each metal atom becomes a cation. The attraction of these cations to the electrons bonds the atoms together in a lattice or framework. Electrons in the sea of electrons are free to move around. Because these electrons can move freely, metals are malleable and good conductors of heat and electricity.

57. Bonding and Malleability of a Metal Figure 22

58. Bonding and Malleability of a Metal Figure 22

59. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS WHAT ARE ALLOYS? Alloys are mixture of two or more elements, one of which is a metal. They are not compounds or molecules.

60. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS WHAT ARE ALLOYS? Alloys are mixture of two or more elements, one of which is a metal. They are not compounds or molecules. Because metal nuclei float in a “sea of electrons”, metal atoms can be replaced by other types of atoms.

61. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS WHAT ARE ALLOYS? Alloys are mixture of two or more elements, one of which is a metal. They are not compounds or molecules. Because metal nuclei float in a “sea of electrons”, metal atoms can be replaced by other types of atoms. Replacing some of the metal atoms with another kind of atom changes the properties of the metal, creating an alloy.

62. WHAT ARE THE TYPES OF BONDS? METALLIC BONDS WHAT ARE ALLOYS? Alloys are mixture of two or more elements, one of which is a metal. They are not compounds or molecules. Because metal nuclei float in a “sea of electrons”, metal atoms can be replaced by other types of atoms. Replacing some of the metal atoms with another kind of atom changes the properties of the metal, creating an alloy. Important alloys: Bronze is an alloy of copper and tin Brass is an alloy of copper and zinc. Stainless steel is an alloy of iron and carbon. Aircraft aluminum is an alloy of aluminum and other metals.