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Lecture Presentation Chapter Ionic and Molecular Compounds Karen C Timberlake General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chapter Ionic and Molecular Compounds Pharmacy technicians work under the supervision of a pharmacist, and their main responsibility is to fill prescriptions by preparing pharmaceutical medications They obtain the proper medication, calculate, measure, and label the patient’s medication General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chapter Readiness Key Math Skills • • Using Positive and Negative Numbers in Calculations (1.4B) Solving Equations (1.4D) Core Chemistry Skills • • Writing Electron Configurations (4.7) Drawing Lewis Symbols (4.8) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc 6.1 Ions: Transfer of Electrons Atoms form positively charged ions when they lose electrons and negatively charged ions when they gain electrons Ionic bonds are formed by the strong attractive forces between positive and negative ions Learning Goal Write the symbols for the simple ions of the representative elements General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Ionic and Covalent Bonds Chemical bonds are formed when atoms lose, gain, or share valence electrons to acquire an octet of eight valence electrons (octet rule) • Ionic bonds occur when valence electrons of a metal atom are transferred to the atom of a nonmetal • Covalent bonds occur when nonmetal atoms share electrons to attain a noble gas arrangement General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Ionic and Covalent Bonds General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Positive Ions: Metals Lose Electrons In ionic bonding, ions form when atoms gain or lose their valence electrons to form a stable electron configuration Metals, Group 1A (1), Group 2A (2), and Group 3A (13) • • have low ionization energies readily lose one or more of their valence electrons to form ions with a positive charge • lose electrons until they have the same number of valence electrons as the nearest noble gas, usually eight valence electrons General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Positive Ions: Loss of Electrons Sodium atoms in Group 1A (1) are neutral, with 11 electrons and 11 protons, they • • lose one electron to have the same number of valence electrons as neon and a filled energy level + will form an ion with 10 electrons, 11 protons, and an ionic charge of 1+: Na General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Positive Ions: Loss of Electrons Magnesium atoms in Group 2A (2) are neutral, and they have 12 electrons and 12 protons They • • will lose electrons to have the same number of valence electrons as neon and a filled energy level + form an ion with 10 electrons, 12 protons, and an ionic charge of 2+: Mg2 General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Negative Ions: Nonmetals Gain Electrons Nonmetals, Group 5A (15), Group 6A (16), and Group 7A (17) • • • have high ionization energies readily gain one or more valence electrons to form ions with a negative charge gain electrons until they have the same number of valence electrons as the nearest noble gas, usually eight valence electrons Core Chemistry Skill Writing Positive and Negative Ions General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc 6.9 Attractive Forces in Compounds The protein shape is stabilized by attractive forces between functional groups of side chains (R groups) on the amino acids, causing it to twist and bend into a specific three-dimensional shape Learning Goal Describe the attractive forces between ions, polar covalent molecules, and nonpolar covalent molecules General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Dipole-Dipole, Hydrogen Bonds In covalent compounds, polar molecules • • exert attractive forces called dipole-dipole attractions form strong dipole attractions called hydrogen bonds between hydrogen atoms bonded to F, O, or N, and a lone pair on F, O, or N Hydrogen bonds are the strongest force between molecules and play a major role in the shape of DNA Core Chemistry Skill Identifying Attractive Forces General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Dispersion Forces Dispersion forces are • • • weak attractions between nonpolar molecules caused by temporary dipoles that develop when molecules bump into each other weak but make it possible for nonpolar molecules to form liquids and solids General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Melting Points and Attractive Forces Melting points of compounds • • are related to the strength of attractive forces between molecules or compounds are lower due to weak forces such as dispersion forces • • are higher due to stronger attractive forces such as hydrogen bonding are highest in ionic compounds due to the strong attractive forces between ions in the compound General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Melting Points and Attractive Forces General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Comparison of Bonding and Attractive Forces General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Study Check Identify the main type of attractive forces that are present in liquids of the following compounds: ionic bonds, dipole-dipole, hydrogen bonds, or dispersion forces A NCl3 B H2O C Br-Br D KCl E NH3 General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Solution Identify the main type of attractive forces that are present in liquids of the following compounds: ionic bonds, dipole-dipole, hydrogen bonds, or dispersion forces A NCl3 dipole-dipole forces B H2Ohydrogen bonds C Br-Br D KCl ionic bonds E NH3 hydrogen bonds dispersion forces General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Attractive Forces, Proteins Proteins are biological molecules with many different functions They are needed for • • • structural components such as cartilage, muscles, hair the formation of enzymes that regulate biological reactions myoglobin and hemoglobin, which transport oxygen in blood and muscle General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Attractive Forces, Proteins Proteins are composed of building blocks called amino acids Every amino acid has a central carbon atom bonded to • + an –NH3 , from an amine • • • − a –COO , from a carboxylic acid an H atom an R group, which is unique for each amino acid General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Attractive Forces, Proteins Several amino acids have R groups or side chains that contain • • • an amide group, –CONH2 a hydroxyl, – OH, group a carboxyl, –COOH, group ionized as carboxylate, – − COO • + an amine, –NH2, group ionized as ammonium, –NH3 General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Attractive Forces, Proteins The primary structure of a protein is its sequence of amino acids It is the sequence of amino acids that determines the protein’s function − Amino acids in a protein are linked by a peptide bond between the COO of one amino acid and the – + NH3 of the next amino acid General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Attractive Forces, Proteins Proteins have a higher level of structure that is determined by the attractive forces between the amino acids When hydrogen bonds form between a hydrogen atom in an N—H group and the oxygen of the C═O group, the protein forms an alpha helix H-bonds can form between the –OH of serine and the –NH of asparagine General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Attractive Forces, Proteins Hydrogen bonds can also form between the polar side chains of the amino acids on the outside of the protein and the –OH and –H of polar water molecules in the external aqueous environment Attractive forces hold the protein in a specific shape General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Concept Map General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc ... arrangement General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Ionic and Covalent Bonds General, Organic, and Biological Chemistry: Structures. .. Cl General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Formulas, Names of Common Ions General, Organic, and Biological Chemistry: ... compounds + 2− Na and O A NaO B AlCl C Al3Cl 2+ 3− Mg and N A MgN B Mg2N3 C Mg3N2 General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake C NaO2 3+ − Al and Cl A AlCl3
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