Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Hewitt/Lyons/Suchocki/Yeh Conceptual Integrated Science Chapter 12 THE NATURE OF CHEMICAL BONDS

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Electron Shells Atoms bond together through their electrons. To learn about bonding, therefore, we need to know something about how the electrons within an atom are organized.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Electron Shells Atoms bond together through their electrons. To learn about bonding, therefore, we need to know something about how the electrons within an atom are organized. Electrons behave as though they are contained within a series of seven concentric shells.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Electron Shells The numbers indicate the maximum number of electrons each shell may contain.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Electron Shells The numbers indicate the maximum number of electrons each shell may contain. Note: This is a “conceptual model” and not a representation of what an atom “looks like.”

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Electron Shells The numbers indicate the maximum number of electrons each shell may contain. Note: Rather, it helps us to understand how the electrons within atoms behave.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The shells are more easily drawn in two dimensions.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The shells are more easily drawn in two dimensions. Each atom has its own configuration of electrons. Elements in the same group have similar configurations, which is why they have similar properties.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Valence electrons: Electrons in the outermost shell of an atom. These are the ones that can participate in chemical bonding. Electron Shells

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Valence electrons: Electrons in the outermost shell of an atom. These are the ones that can participate in chemical bonding. Electron-dot structure: A notation showing the valence electrons surrounding the atomic symbol. Electron Shells

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Valence electrons: Electrons in the outermost shell of an atom. These are the ones that can participate in chemical bonding. Electron-dot structure: A notation showing the valence electrons surrounding the atomic symbol. Electron Shells

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley For heavier atoms, some valence electrons are more available than others. Krypton, for example, has 18 valence electrons, but only eight of these are typically shown within an electron-dot structure. These are the eight that extend farthest away from the nucleus. Special Note Kr

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Note that elements within the same group have the same electron-dot structure. Electron Shells

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Sodium, Na, atomic number 11, has only one valence electron. Upon losing this electron, what other atom in the periodic table does the sodium thus resemble? A.Neon, Ne, atomic number 10 B.Magnesium, Mg, atomic number 12 C.Lithium, Li, atomic number 3 D.Sodium can only resemble sodium. Electron Shells CHECK YOUR NEIGHBOR

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Sodium, Na, atomic number 11, has only one valence electron. Upon losing this electron, what other atom in the periodic table does the sodium thus resemble? A.Neon, Ne, atomic number 10 B.Magnesium, Mg, atomic number 12 C.Lithium, Li, atomic number 3 D.Sodium can only resemble sodium. Electron Shells CHECK YOUR ANSWER Explanation: With 10 electrons, the sodium has enough electrons to fill the first and second shells, just like neon, Ne.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Ionic Bond Ion: An atom that has lost or gained one or more electrons.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Ionic Bond Ion: An atom that has lost or gained one or more electrons.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Ionic Bond Ion: An atom that has lost or gained one or more electrons. Ionic Bond: The electrical force of attraction between oppositely charged ions.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Ionic Bond Ion: An atom that has lost or gained one or more electrons. Ionic bond: The electrical force of attraction between oppositely charged ions. Na + F−F−

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Ionic Bond Ion: An atom that has lost or gained one or more electrons. Ionic bond: The electrical force of attraction between oppositely charged ions. Molecular ion: Typically formed by the loss or gain of a hydrogen ion, H +.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Molecular ion: Typically formed by the loss or gain of a hydrogen ion, H +. H O H H+H+ WaterHydrogen ion The Ionic Bond

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Molecular ion: Typically formed by the loss or gain of a hydrogen ion, H +. H O H H+H+ The Ionic Bond

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Molecular ion: Typically formed by the loss or gain of a hydrogen ion, H +. H O H H+H+ The Ionic Bond

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Molecular ion: Typically formed by the loss or gain of a hydrogen ion, H +. H O H H+H+ The Ionic Bond

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Molecular ion: Typically formed by the loss or gain of a hydrogen ion, H +. H O H H + Hydronium ion, H 3 O + The Ionic Bond

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley A.AlO B.Al 3 O 2 C.Al 2 O 3 D.Al 6 O 6 The Ionic Bond CHECK YOUR NEIGHBOR What is the chemical formula for a compound made of aluminum ions, Al 3+, and oxygen ions, O 2– ?

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley A.AlO B.Al 3 O 2 C.Al 2 O 3 D.Al 6 O 6 The Ionic Bond CHECK YOUR ANSWER What is the chemical formula for a compound made of aluminum ions, Al 3+, and oxygen ions, O 2– ?

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley A.MgO B.Mg 2 O 2 C.Mg 4 O 4 D.Any of the above The Ionic Bond CHECK YOUR NEIGHBOR What is the chemical formula for a compound made of magnesium ions, Mg 2+, and oxygen ions, O 2– ?

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley A.MgO B.Mg 2 O 2 C.Mg 4 O 4 D.Any of the above The Ionic Bond CHECK YOUR ANSWER What is the chemical formula for a compound made of magnesium ions, Mg 2+, and oxygen ions, O 2– ? Explanation: The chemical formula is used to show the ratio by which atoms combine. By convention, the lowest numbers are preferred, so 1:1 is used rather than 2:2. The numeral 1, however, is implied when no subscript is written.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Naming Ionic Compounds Guideline 1 –Name the ions (that’s all there is) —Start with the element farthest to the left in the periodic table. (the metal) —Name it (some exceptions latter)

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Guideline 1 —For the element to the right,(the nonmetal) add the suffix -ide. Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Guideline 1 —Start with the element farthest to the left in the periodic table. —For the element to the right, add the suffix -ide. Example: NaCl Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley NaCl Sodium Example: NaCl Chlorine Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley NaCl Sodium Example: NaCl chloride Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley NaCl Sodium Example: NaCl chloride Naming Compounds

Polyatomic Ions –The rules still apply. Name the ions. –Do NOT change the endings of any polyatomic ion. Example: NaOH Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley

Polyatomic Ions –The rules still apply. Name the ions. –Do NOT change the endings of any polyatomic ion. Example: Sodium Hydrogen carbonate Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley

Multivalent Atoms Some metals may not always have the same charge. –Iron can be Fe +2 or Fe +3 –To name them name the charge Fe +2 iron (II) Fe +3 iron (III) –How do you know which metals do this? Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley

The Covalent Bond The type of electrical attraction in which atoms are held together by their mutual attraction for shared electrons.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The type of electrical attraction in which atoms are held together by their mutual attraction for shared electrons. There are two electrons within a single covalent bond.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The type of electrical attraction in which atoms are held together by their mutual attraction for shared electrons. There are two electrons within a single covalent bond. The covalent bond is represented using a straight line.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The type of electrical attraction in which atoms are held together by their mutual attraction for shared electrons. There are two electrons within a single covalent bond. The covalent bond is represented using a straight line. F — FF

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The number of covalent bonds an atom can form equals its number of unpaired valence electrons.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The number of covalent bonds an atom can form equals its number of unpaired valence electrons.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The number of covalent bonds an atom can form equals its number of unpaired valence electrons.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The number of covalent bonds an atom can form equals its number of unpaired valence electrons.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The number of covalent bonds an atom can form equals its number of unpaired valence electrons. Multiple covalent bonds are possible.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley The Covalent Bond The number of covalent bonds an atom can form equals its number of unpaired valence electrons. Multiple covalent bonds are possible.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Naming Compounds Guideline 1 —Start with the element farthest to the left in the periodic table. —For the element to the right, add the suffix -ide. Guideline 2 —With different possible combinations of elements, use prefixes to remove ambiguity.

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley mono- di- tri- tetra Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley CO 2 Examples: Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley CO 2 carbon monoxide carbon dioxide Examples: Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Examples: H O 2 dihydrogen monoxide dihydrogen dioxide 2 2 Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Examples: H O 2 dihydrogen monoxide dihydrogen dioxide 2 2 Would you drink this?? Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Examples: H O 2 “Water” “Hydrogen peroxide” 2 2 Naming Compounds

Copyright © 2007 Pearson Education, Inc., publishing as Pearson Addison Wesley Naming Compounds Guideline 1 —Start with the element farthest to the left in the periodic table. —For the element to the right, add the suffix -ide. Guideline 2 —With different possible combinations of elements, use prefixes to remove ambiguity. Guideline 3 —Common names are sometimes used for convenience.