This page intentionally left blank This page intentionally left blank smi11153_endpapers_front.indd Periodic Table of the Elements 1A 8A 18 1 H 1.0079 3A 13 4A 14 5A 15 6A 16 7A 17 4.0026 10 Li Be B 6.941 9.0122 10.811 11 Na 12 Mg 22.9898 24.3050 19 K 20 Ca 13 3B 4B 5B 6B 7B 21 22 23 24 25 Sc 39.0983 40.078 44.9559 37 38 Rb Sr 85.4678 87.62 55 Cs 56 Ba 39 Y 87 88 Ti V 47.88 40 41 Zr 57 La Nb 72 73 Hf Cr Mn 8B 26 27 Fe Ta 42 43 Mo Tc 95.94 (98) 74 W 75 Re 178.49 180.9479 183.84 186.207 190.2 192.22 108 109 Mt (276) Db Sg Bh Hs (268) (271) (272 ) (270) 58 Ce 59 Pr 107 77 Rf Ac (227) 106 60 Nd 140.115 140.9076 144.24 90 Th 91 Pa 92 U 232.0381 231.03588 238.0289 45 Rh 76 Os (267) Ra (226) 2B 12 28 29 30 Ni 46 Pd 61 Ir 62 78 Pt O 31 F Ne 14 Si 15 P 16 S 32 33 34 17 Ar 35.453 39.948 35 Ga Ge As Se Br Kr 63.546 65.41 69.723 72.64 74.9216 78.96 79.904 83.80 52 53 47 48 Cd 79 Au 80 Hg 49 In 50 Sn 51 Sb 114.82 118.710 121.760 81 Tl 82 83 Te I 84 85 86 Pb Bi Po At Rn 207.2 208.9804 (209) (210) (222) Ds Rg 114 115 116 118 (281) (280) (285) (284) (289) (289) (293) (294) 63 Eu (145) 150.36 151.964 64 Gd 65 Tb 66 Dy – 67 Ho – 68 Er 127.60 126.9045 131.29 113 – 54 Xe 112 – 36 Zn Ag 18 Cl 111 110 Sm 94 N 26.9815 28.0855 30.9738 32.066 195.08 196.9665 200.59 204.3833 Pm 93 Al C 12.011 14.0067 15.9994 18.9984 20.1797 Cu 101.07 102.9055 106.42 107.8682 112.411 104 Fr 105 44 Ru 89 (223) Co 10 1B 11 50.9415 51.9961 54.9380 55.845 58.9332 58.693 88.9059 91.224 92.9064 132.9054 137.327 138.9055 He 2A – 69 Tm – 70 Yb 71 Lu 157.25 158.9253 162.50 164.9303 167.26 168.9342 173.04 174.967 95 96 (247) 97 98 99 100 101 102 103 (262) Np Pu Am Cm Bk Cf Es Fm Md No (237) (244) (243) (247) (251) (252) (257) (258) (259) Lr 11/18/10 9:20 AM The Elements Element Symbol Actinium Aluminum Americium Antimony Argon Arsenic Astatine Barium Berkelium Beryllium Bismuth Bohrium Boron Bromine Cadmium Calcium Californium Carbon Cerium Cesium Chlorine Chromium Cobalt Copper Curium Darmstadtium Dubnium Dysprosium Einsteinium Erbium Europium Fermium Fluorine Francium Gadolinium Gallium Germanium Gold Hafnium Hassium Helium Holmium Hydrogen Indium Iodine Iridium Iron Krypton Lanthanum Lawrencium Lead Lithium Lutetium Magnesium Manganese Meitnerium Mendelevium Mercury Molybdenum Neodymium Ac Al Am Sb Ar As At Ba Bk Be Bi Bh B Br Cd Ca Cf C Ce Cs Cl Cr Co Cu Cm Ds Db Dy Es Er Eu Fm F Fr Gd Ga Ge Au Hf Hs He Ho H In I Ir Fe Kr La Lr Pb Li Lu Mg Mn Mt Md Hg Mo Nd Atomic Number 89 13 95 51 18 33 85 56 97 83 107 35 48 20 98 58 55 17 24 27 29 96 110 105 66 99 68 63 100 87 64 31 32 79 72 108 67 49 53 77 26 36 57 103 82 71 12 25 109 101 80 42 60 Relative Atomic Mass* (227) 26.9815 (243) 121.760 39.948 74.9216 (210) 137.327 (247) 9.0122 208.9804 (272) 10.811 79.904 112.411 40.078 (251) 12.011 140.115 132.9054 35.453 51.9961 58.9332 63.546 (247) (281) (268) 162.50 (252) 167.26 151.964 (257) 18.9984 (223) 157.25 69.723 72.64 196.9665 178.49 (270) 4.0026 164.9303 1.0079 114.82 126.9045 192.22 55.845 83.80 138.9055 (262) 207.2 6.941 174.967 24.3050 54.9380 (276) (258) 200.59 95.94 144.24 Element Symbol Neon Neptunium Nickel Niobium Nitrogen Nobelium Osmium Oxygen Palladium Phosphorus Platinum Plutonium Polonium Potassium Praseodymium Promethium Protactinium Radium Radon Rhenium Rhodium Roentgenium Rubidium Ruthenium Rutherfordium Samarium Scandium Seaborgium Selenium Silicon Silver Sodium Strontium Sulfur Tantalum Technetium Tellurium Terbium Thallium Thorium Thulium Tin Titanium Tungsten Uranium Vanadium Xenon Ytterbium Yttrium Zinc Zirconium Ne Np Ni Nb N No Os O Pd P Pt Pu Po K Pr Pm Pa Ra Rn Re Rh Rg Rb Ru Rf Sm Sc Sg Se Si Ag Na Sr S Ta Tc Te Tb Tl Th Tm Sn Ti W U V Xe Yb Y Zn Zr Atomic Number 10 93 28 41 102 76 46 15 78 94 84 19 59 61 91 88 86 75 45 111 37 44 104 62 21 106 34 14 47 11 38 16 73 43 52 65 81 90 69 50 22 74 92 23 54 70 39 30 40 112** 113 114 115 116 118 Relative Atomic Mass* 20.1797 (237) 58.693 92.9064 14.0067 (259) 190.2 15.9994 106.42 30.9738 195.08 (244) (209) 39.0983 140.9076 (145) 231.03588 (226) (222) 186.207 102.9055 (280) 85.4678 101.07 (267) 150.36 44.9559 (271) 78.96 28.0855 107.8682 22.9898 87.62 32.066 180.9479 (98) 127.60 158.9253 204.3833 232.0381 168.9342 118.710 47.88 183.84 238.0289 50.9415 131.29 173.04 88.9059 65.41 91.224 (285) (284) (289) (289) (293) (294) *Values in parentheses represent the mass number of the most stable isotope **The names and symbols for elements 112–116 and 118 have not been chosen smi11153_endpapers_front.indd 11/18/10 9:20 AM General, Organic, & Biological Chemistry Janice Gorz Gorzynski Smith University of H Hawai’i at Ma-noa TM smi11153_FM_i-xxii.indd i 11/18/10 11:16 AM TM PRINCIPLES OF GENERAL, ORGANIC, & BIOLOGICAL CHEMISTRY Published by McGraw-Hill, a business unit of The McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY 10020 Copyright © 2012 by The McGraw-Hill Companies, Inc All rights reserved No part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written consent of The McGraw-Hill Companies, Inc., including, but not limited to, in any network or other electronic storage or transmission, or broadcast for distance learning Some ancillaries, including electronic and print components, may not be available to customers outside the United States This book is printed on acid-free paper DOW/DOW ISBN 978–0–07–351115–3 MHID 0–07–351115–3 Vice President, Editor-in-Chief: Marty Lange Vice President, EDP: Kimberly Meriwether David Senior Director of Development: Kristine Tibbetts Publisher: Ryan Blankenship Sponsoring Editor: Todd L Turner Senior Developmental Editor: Donna Nemmers Executive Marketing Manager: Tamara L Hodge Senior Project Manager: Jayne L Klein Senior Buyer: Laura Fuller Senior Media Project Manager: Christina Nelson Senior Designer: Laurie B Janssen Cover Image: © Matt Brasier / Masterfile Lead Photo Research Coordinator: Carrie K Burger Photo Research: Mary Reeg Compositor: Precision Graphics Typeface: 10/12.5 Times LT Std Printer: R R Donnelley All credits appearing on page or at the end of the book are considered to be an extension of the copyright page Library of Congress Cataloging-in-Publication Data Smith, Janice G Principles of general, organic, and biological chemistry / Janice Gorzynski Smith 1st ed p cm Includes index ISBN 978–0–07–351115–3 — ISBN 0–07–351115–3 (hard copy : alk paper) Chemistry Textbooks Chemistry, Inorganic Textbooks Biochemistry Textbooks I Title QD31.3.S634 2012 540 dc22 2010038944 www.mhhe.com smi11153_FM_i-xxii.indd ii 11/18/10 11:17 AM To my family smi11153_FM_i-xxii.indd iii 11/18/10 11:17 AM About the Author Janice Gorzynski Smith was born in Schenectady, New York, and grew up following the Yankees, listening to the Beatles, and water skiing on Sacandaga Reservoir She became interested in chemistry in high school, and went on to major in chemistry at Cornell University where she received an A.B degree summa cum laude Jan earned a Ph.D in Organic Chemistry from Harvard University under the direction of Nobel Laureate E J Corey, and she also spent a year as a National Science Foundation National Needs Postdoctoral Fellow at Harvard During her tenure with the Corey group she completed the total synthesis of the plant growth hormone gibberellic acid Following her postdoctoral work Jan joined the faculty of Mount Holyoke College, where she was employed for 21 years During this time she was active in teaching organic chemistry lecture and lab courses, conducting a research program in organic synthesis, and serving as department chair Her organic chemistry class was named one of Mount Holyoke’s “Don’t-miss courses” in a survey by Boston magazine After spending two sabbaticals amidst the natural beauty and diversity in Hawai‘i in the 1990s, Jan and her family moved there permanently in 2000 She is a faculty member at the University of Hawai‘i at Ma- noa, where she has taught a one-semester organic and biological chemistry course for nursing students as well as the twosemester organic chemistry lecture and lab courses She has also served as the faculty advisor to the student affiliate chapter of the American Chemical Society In 2003, she received the Chancellor’s Citation for Meritorious Teaching Jan resides in Hawai‘i with her husband Dan, an emergency medicine physician She has four children: Matthew and Zachary (scuba photo on p 167); Jenna, a law student at Temple University in Philadelphia; and Erin, a 2006 graduate of Brown University School of Medicine and co-author of the Student Study Guide/Solutions Manual for this text When not teaching, writing, or enjoying her family, Jan bikes, hikes, snorkels, and scuba dives in sunny Hawai‘i, and time permitting, enjoys travel and Hawaiian quilting iv smi11153_FM_i-xxii.indd iv 11/18/10 11:17 AM Contents in Brief Matter and Measurement Atoms and the Periodic Table 34 Ionic and Covalent Compounds 68 Energy and Matter 105 Chemical Reactions Gases 127 167 Solutions 194 Acids and Bases 222 Nuclear Chemistry 256 10 11 12 13 Introduction to Organic Molecules 283 14 15 16 17 18 Carbohydrates Unsaturated Hydrocarbons 322 Organic Compounds That Contain Oxygen or Sulfur 353 Carboxylic Acids, Esters, Amines, and Amides 391 Lipids 427 459 Amino Acids, Proteins, and Enzymes Nucleic Acids and Protein Synthesis Energy and Metabolism 492 527 560 v smi11153_FM_i-xxii.indd v 11/18/10 11:17 AM 2.8 59 Periodic Trends • Each dot represents one electron • The dots are placed on the four sides of an element symbol • For one to four valence electrons, single dots are used With more than four electrons, the dots are paired The location of the dots around the symbol—side, top, or bottom—does not matter Each of the following representations for the five valence electrons of nitrogen is equivalent N N N N SAMPLE PROBLEM 2.13 Write an electron-dot symbol for each element: (a) sodium; (b) phosphorus Analysis Write the symbol for each element and use the group number to determine the number of valence electrons for a main group element Represent each valence electron with a dot Solution a The symbol for sodium is Na Na is in group 1A and has one valence electron Electrondot symbol: Na b The symbol for phosphorus is P P is in group 5A and has five valence electrons Electrondot symbol: P PROBLEM 2.28 Give the electron-dot symbol for each element: (a) bromine; (b) lithium; (c) aluminum; (d) sulfur; (e) neon 2.8 Periodic Trends Many properties of atoms exhibit periodic trends; that is, they change in a regular way across a row or down a column of the periodic table Two properties that illustrate this phenomenon are atomic size and ionization energy 2.8A Atomic Size The size of an atom is measured by its atomic radius—that is, the distance from the nucleus to the outer edge of the valence shell Two periodic trends characterize the size of atoms • The size of atoms increases down a column of the periodic table, as the valence electrons are farther from the nucleus 17 Cl 35 Br 53 Increasing size For group 7A: F I smi11153_ch02_034-067.indd 59 9/15/10 9:04 AM 60 Chapter Atoms and the Periodic Table • The size of atoms decreases across a row of the periodic table as the number of protons in the nucleus increases An increasing number of protons pulls the electrons closer to the nucleus, so the atom gets smaller For period 2: C N O F Increasing size PROBLEM 2.29 Rank the atoms in each group in order of increasing size a boron, carbon, neon c silicon, sulfur, magnesium b calcium, magnesium, beryllium d krypton, neon, xenon 2.8B Ionization Energy Since a negatively charged electron is attracted to a positively charged nucleus, energy is required to remove an electron from a neutral atom The more tightly the electron is held, the greater the energy required to remove it Removing an electron from a neutral atom forms a cation Na neutral atom + energy Na+ ionization energy cation + e− • The ionization energy is the energy needed to remove an electron from a neutral atom • A cation is positively charged, and has fewer electrons than the neutral atom Two periodic trends characterize ionization energy • Ionization energies decrease down a column of the periodic table as the valence electrons get farther from the positively charged nucleus Increasing ionization energy For group 1A: smi11153_ch02_034-067.indd 60 H Li 11 Na 19 K 9/15/10 9:04 AM 61 Key Concepts • Ionization energies generally increase across a row of the periodic table as the number of protons in the nucleus increases For period 2: C N O F Increasing ionization energy PROBLEM 2.30 Arrange the elements in each group in order of increasing ionization energy a phosphorus, silicon, sulfur c carbon, fluorine, beryllium b magnesium, calcium, beryllium d neon, krypton, argon KEY TERMS Actinide (2.4) Electronic configuration (2.6) Neutron (2.2) Alkali metal (2.4) Element (2.1) Noble gas (2.4) Alkaline earth element (2.4) Ground state (2.6) Nonmetal (2.1) Atom (2.1) Group (2.4) Nucleus (2.2) Atomic mass unit (2.2) Group number (2.4) Orbital (2.5) Atomic number (2.2) Halogen (2.4) Period (2.4) Atomic weight (2.3) Inner transition metal element (2.4) Periodic table (2.1) Building-block element (2.1) Ionization energy (2.8) p Orbital (2.5) Cation (2.8) Isotope (2.3) Proton (2.2) Chemical formula (2.1) Lanthanide (2.4) Shell (2.5) Compound (2.1) Main group element (2.4) s Orbital (2.5) Deuterium (2.3) Major mineral (Macronutrient, 2.1) Trace element (Micronutrient, 2.1) Electron (2.2) Mass number (2.2) Transition metal element (2.4) Electron cloud (2.2) Metal (2.1) Tritium (2.3) Electron-dot symbol (2.7) Metalloid (2.1) Valence electron (2.7) KEY CONCEPTS ❶ ❷ How is the name of an element abbreviated and how does the periodic table help to classify it as a metal, nonmetal, or metalloid? (2.1) • An element is abbreviated by a one- or two-letter symbol The periodic table contains a stepped line from boron to astatine All metals are located to the left of the line All nonmetals except hydrogen are located to the right of the line The seven elements located along the line are metalloids What are the basic components of an atom? (2.2) • An atom is composed of two parts: a dense nucleus containing positively charged protons and neutral neutrons, and an electron cloud containing negatively charged electrons smi11153_ch02_034-067.indd 61 Most of the mass of an atom resides in the nucleus, while the electron cloud contains most of its volume • The atomic number (Z) of a neutral atom tells the number of protons and the number of electrons The mass number (A) is the sum of the number of protons (Z) and the number of neutrons ❸ What are isotopes and how are they related to the atomic weight? (2.3) • Isotopes are atoms that have the same number of protons but a different number of neutrons The atomic weight is the weighted average of the mass of the naturally occurring isotopes of a particular element 9/15/10 9:04 AM 62 ❹ Chapter Atoms and the Periodic Table What are the basic features of the periodic table? (2.4) • The periodic table is a schematic of all known elements, arranged in rows (periods) and columns (groups), organized so that elements with similar properties are grouped together • The vertical columns are assigned group numbers using two different numbering schemes—1–8 plus the letters A or B; or 1–18 • The periodic table is divided into the main group elements (groups 1A–8A), the transition metals (groups 1B–8B), and the inner transition metals located in the two rows below the main table ❺ How are electrons arranged around an atom? (2.5) • Electrons occupy discrete energy levels (numbered 1, 2, 3, and so on) that contain orbitals (s, p, d, and f ) • Each orbital can hold two electrons ❻ What rules determine the electronic configuration of an atom? (2.6) • To write the ground state electronic configuration of an atom, electrons are added to the lowest energy orbitals, giving each orbital two electrons • Electron configuration is shown using superscripts to indicate how many electrons an orbital contains For example, the electron configuration of the six electrons in a carbon atom is 1s22s22p2 ❼ How is the location of an element in the periodic table related to its number of valence electrons? (2.7) • Elements in the same group have the same number of valence electrons ❽ What is an electron-dot symbol? (2.7) • An electron-dot symbol uses a dot to represent each valence electron around the symbol for an element ❾ How are atomic size and ionization energy related to location in the periodic table? (2.8) • The size of an atom decreases across a row and increases down a column • Ionization energy—the energy needed to remove an electron from an atom—increases across a row and decreases down a column UNDERSTANDING KEY CONCEPTS 2.31 Identify the elements used in each example of molecular art a b 2.33 Give the following information about the atom shown: (a) the number of protons and neutrons in the nucleus; (b) the atomic number; (c) the mass number; (d) the number of electrons in the neutral atom; and (e) the element symbol + + + + + 2.32 Write a chemical formula for each example of molecular art a b c 2.34 Give the following information about the atom shown: (a) the number of protons and neutrons in the nucleus; (b) the atomic number; (c) the mass number; (d) the number of electrons in the neutral atom; and (e) the element symbol + + + + smi11153_ch02_034-067.indd 62 + + + 9/15/10 9:04 AM 63 Additional Problems 2.35 Selenium is a micronutrient necessary for certain enzymes that block unwanted oxidation reactions Selenium is also needed for proper functioning of the thyroid gland Answer the following questions about the element selenium a What is its element symbol? b To what group number and period does selenium belong? c Is selenium a main group element, transition metal, or inner transition metal? d How many valence electrons does selenium contain? e Draw an isotope symbol for a selenium atom that contains 46 neutrons in the nucleus 2.36 Answer the following questions about the element silicon, a micronutrient needed for healthy bones, nails, skin, and hair a What is its element symbol? b To what group number and period does silicon belong? c Is silicon a main group element, transition metal, or inner transition metal? d Draw an isotope symbol for a silicon atom that contains 14 neutrons in the nucleus 2.37 (a) What element has the ground state electronic configuration 1s22s22p63s23p1? (b) How many valence electrons does this element contain? (c) Give the group number and the period number for the element 2.38 (a) Write the ground state electronic configuration for the element silicon (b) How many valence electrons does silicon contain? (c) Give an electron-dot symbol for silicon 2.39 Which element in each pair is larger? a bromine and iodine b carbon and nitrogen 2.40 Which element in each pair has its valence electrons farther from the nucleus? a sodium and magnesium b neon and krypton ADDITIONAL PROBLEMS Elements 2.41 Give the name of the elements in each group of three element symbols a Au, At, Ag c S, Si, Sn b N, Na, Ni d Ca, Cr, Cl 2.42 What element(s) are designated by each symbol or group of symbols? a CU and Cu c Ni and NI b Os and OS d BIN, BiN, and BIn 2.43 Does each chemical formula represent an element or a compound? b H2O2 c S8 d Na2CO3 e C60 a H2 2.44 Identify the elements in each chemical formula and tell how many atoms of each are present a K2Cr2O7 b C5H8NNaO4 (MSG, flavor enhancer) c C10H16N2O3S (vitamin B7) 2.45 Identify the element that fits each description a an alkali metal in period b a transition metal in period 5, group c a main group element in period 3, group 7A d a halogen in period 2.46 Identify the element that fits each description a an alkaline earth element in period b a noble gas in period c a transition metal in period 4, group 11 d a transition metal in period 6, group 10 smi11153_ch02_034-067.indd 63 2.47 Give all of the terms that apply to each element: [1] metal; [2] nonmetal; [3] metalloid; [4] alkali metal; [5] alkaline earth element; [6] halogen; [7] noble gas; [8] main group element; [9] transition metal; [10] inner transition metal a sodium c xenon b silver d platinum 2.48 Give all of the terms that apply to each element: [1] metal; [2] nonmetal; [3] metalloid; [4] alkali metal; [5] alkaline earth element; [6] halogen; [7] noble gas; [8] main group element; [9] transition metal; [10] inner transition metal a bromine c cesium b calcium d gold Atomic Structure 2.49 Complete the following table for neutral elements Element Symbol Atomic Number Mass Number a C 12 b 31 c d Mg Number of Protons Number of Neutrons Number of Electrons 15 35 30 24 2.50 For the given atomic number (Z) and mass number (A): [1] identify the element; [2] give the element symbol; [3] give the number of protons, neutrons, and electrons a Z = 10, A = 20 c Z = 38, A = 88 b Z = 13, A = 27 d Z = 55, A = 133 9/15/10 9:04 AM 64 Chapter Atoms and the Periodic Table Periodic Table 2.51 Label each region on the periodic table a noble gases d alkaline earth elements b period e transition metals c group 4A f group 10 2.62 Write the element symbol that fits each description Use a superscript for the mass number and a subscript for the atomic number a an element that contains 10 protons and 12 neutrons b an element with atomic number 24 and mass number 52 2.63 Can the neutral atoms of two different elements have the same number of electrons? Explain 2.64 Can the neutral atoms of two different elements have the same number of neutrons? Explain 2.52 Identify each highlighted element in the periodic table and give its [1] element name and symbol; [2] group number; [3] period; [4] classification (i.e., main group element, transition metal, or inner transition metal) (b) (a) (d) (e) Electronic Configuration 2.65 What is the difference between a 1s and 2s orbital? 2.66 What is the difference between a 2s and 2p orbital? 2.67 What element(s) in the first three periods fit each description? a The element contains five electrons in the 3p orbitals b There is one valence electron c The element contains four electrons in the second energy level 2.53 What element is located in group 1A but is not an alkali metal? 2.68 What element(s) in the first three periods fit each description? a The element contains three electrons in the 3p orbitals b There are two valence electrons c The element contains five electrons in the second shell 2.54 Name two elements in the periodic table that have chemical properties similar to carbon 2.69 Write out the electronic configuration for each element: (a) B; (b) Mg 2.55 Classify each element in the fourth row of the periodic table as a metal, nonmetal, or metalloid 2.70 Write out the electronic configuration for each element: (a) nitrogen; (b) argon 2.56 Which group(s) in the periodic table contain only nonmetals? 2.71 Give the total number of electrons, the number of valence electrons, and the identity of the element with each electronic configuration b 1s22s22p63s1 a 1s22s22p63s23p4 (c) Isotopes and Atomic Weight 2.57 The most common isotope of oxygen has a mass number of 16, but two other isotopes having mass numbers of 17 and 18 are also known For each isotope, give the following information: (a) the number of protons; (b) the number of neutrons; (c) the number of electrons in the neutral atom; (d) the group number; (e) the element symbols using superscripts and subscripts 2.58 The three most common isotopes of tin have mass numbers 116, 118, and 120 For each isotope, give the following information: (a) the number of protons; (b) the number of neutrons; (c) the number of electrons in the neutral atom; (d) the group number; (e) the element symbols using superscripts and subscripts 2.59 How many protons, neutrons, and electrons are contained in each element? b 1375Cl c 1364 S a 1237 Al 2.60 Give the number of protons, neutrons, and electrons in each element: (a) silver-115; (b) Au-197; (c) Rn-222; (d) osmium-192 2.61 Write the element symbol that fits each description, using a superscript for the mass number and a subscript for the atomic number a an element that contains 53 protons and 74 neutrons b an element with 35 electrons and a mass number of 79 smi11153_ch02_034-067.indd 64 2.72 Give the total number of electrons, the number of valence electrons, and the identity of the element with each electronic configuration b 1s22s22p3 a 1s22s22p63s23p6 2.73 How an alkali metal and an alkaline earth element in the same row differ in the electronic configuration of the valence shell electrons? 2.74 How a halogen and a noble gas in the same row differ in the electronic configuration of the valence shell electrons? 2.75 For each element, give the following information: [1] total number of electrons; [2] group number; [3] number of valence electrons; [4] period a carbon b calcium c krypton 2.76 For each element, give the following information: [1] total number of electrons; [2] group number; [3] number of valence electrons; [4] period a oxygen b sodium c phosphorus 2.77 How many valence electrons does an element in each group contain: (a) 2A; (b) 4A; (c) 7A? 9/15/10 9:04 AM 65 Beyond the Classroom 2.78 In what shell the valence electrons reside for an element in period: (a) 2; (b) 3; (c) 4? 2.79 Give the number of valence electrons in each element a sulfur b chlorine c barium 2.80 Give the number of valence electrons in each element a neon b rubidium c aluminum 2.81 Write an electron-dot symbol for each element: (a) beryllium; (b) iodine; (c) magnesium; (d) argon 2.82 Write an electron-dot symbol for each element: (a) K; (b) B; (c) F; (d) Ca Periodic Trends 2.83 Which element in each pair is larger? a silicon and potassium b chlorine and selenium 2.84 Which element in each pair has its valence electrons farther from the nucleus? a carbon and fluorine b argon and bromine 2.85 For each pair of elements in Problem 2.83, label the element with the higher ionization energy 2.86 For each pair of elements in Problem 2.84, label the element from which it is easier to remove an electron 2.87 Rank the following elements in order of increasing size: sulfur, silicon, oxygen, magnesium, and fluorine 2.88 Rank the following elements in order of increasing ionization energy: nitrogen, fluorine, magnesium, sodium, and phosphorus Applications 2.89 Sesame seeds, sunflower seeds, and peanuts are good dietary sources of the trace element copper Copper is needed for the synthesis of neurotransmitters, compounds that transmit nerve signals from one nerve cell to another Copper is also needed for the synthesis of collagen, a protein found in bone, tendons, teeth, and blood vessels a Give the element symbol, group number, and period number for copper b Classify copper as a main group element, transition metal, or inner transition metal c If a 60.-kg individual contains 60 mg of copper in his body, how many grams of copper are present in each gram of body mass? Write the number in scientific notation 2.90 Platinum is a precious metal used in a wide variety of products Besides fine jewelry, platinum is also the catalyst found in the catalytic converters of automobile exhaust systems, and platinum-containing drugs like cisplatin are used to treat some lung and ovarian cancers Answer the following questions about the element platinum a What is its element symbol? b What group number and period are assigned to platinum? c What is its atomic number? d Is platinum classified as a main group element, transition metal, or inner transition metal? 2.91 Answer the following questions about the macronutrients sodium, potassium, and chlorine a Is each element classified as a metal, nonmetal, or metalloid? b Which element has the smallest atomic radius? c Which element has the largest atomic radius? d Which element has the largest ionization energy? e Which element has the smallest ionization energy? f How many valence electrons does each element possess? 2.92 Answer the following questions about the macronutrients calcium, magnesium, and sulfur a Is each element classified as a metal, nonmetal, or metalloid? b Which element has the smallest atomic radius? c Which element has the largest atomic radius? d Which element has the largest ionization energy? e Which element has the smallest ionization energy? f How many valence electrons does each element possess? CHALLENGE PROBLEM 2.93 Strontium-90 is a radioactive element formed in nuclear reactors When an unusually high level of strontium is released into the air, such as occurred during the Chernobyl nuclear disaster in 1986, the strontium can be incorporated into the bones of exposed individuals High levels of strontium can cause bone cancer and leukemia Why does Sr-90 cause this particular health problem? (Hint: What macronutrient has similar chemical properties to strontium?) BEYOND THE CLASSROOM 2.94 Research why long-term exposure to high levels of lead causes harmful effects on the human body Besides leaded gasoline, where might an individual be exposed to lead? How is lead removed from the body when a person is diagnosed with lead poisoning? 2.95 Calculate how much lead your car would emit into the atmosphere in a year if one gallon of gasoline contained about g of lead Make needed assumptions—such as the number of miles you drive in a year and the number of miles per gallon smi11153_ch02_034-067.indd 65 of gas your car gets—based on your family’s driving habits, and include them in your calculation Compare results with other class members with different driving habits 2.96 Pick one of the trace elements in Figure 2.2 and research why it is needed in the body From what dietary sources we obtain the nutrient and how much we need? What is the recommended daily intake of the trace element, and what symptoms result from its deficiency? 9/15/10 9:04 AM 66 Chapter Atoms and the Periodic Table ANSWERS TO SELECTED PROBLEMS 2.1 a Ca b Rn c N d Au 2.3 a neon b sulfur c iodine d silicon e boron f mercury 2.5 As, B, Si: metalloids Cr, Co, Cu, Fe, Mn, Mo, Ni, Zn: metals F, I, Se: nonmetals 2.6 2.7 2.9 c fluorine 2.10 Atomic Number a b c d e 11 20 47 78 Element Protons Electrons Helium Sodium Calcium Silver Platinum 11 20 47 78 11 20 47 78 2.11 a protons and neutrons b atomic number 4, mass number c beryllium 2.12 Protons Neutrons Electrons 17 14 92 18 14 146 17 14 92 a b c 2.13 iodine, 53 electrons, mass number 127 2.15 Atomic Number Mass Number Protons Neutrons Electrons 51 13 121 51 70 51 a b 2.26 a b c d electrons, valence electron, lithium electrons, valence electrons, nitrogen 12 electrons, valence electrons, magnesium 15 electrons, valence electrons, phosphorus 2.27 a b c d 2.28 a 2.29 a b c d b Br Protons Electrons Atomic Number Mass Number 12 12 12 12 12 12 12 12 12 24 25 26 2.17 a atomic number 27 and atomic weight 58.93 b 27 protons and 27 electrons 2.19 Element a b c d e Oxygen Calcium Phosphorus Platinum Iodine Period Group 6A (or 16) 2A (or 2) 5A (or 15) 8B (or 10) 7A (or 17) 2.21 a titanium, Ti, group 4B (or 4), period 4, transition metal b phosphorus, P, group 5A (or 15), period 3, main group element c dysprosium, Dy, no group number, period 6, inner transition element smi11153_ch02_034-067.indd 66 c Li Al d S e Ne neon, carbon, boron beryllium, magnesium, calcium sulfur, silicon, magnesium neon, krypton, xenon 2.31 a carbon (black), oxygen (red) b carbon (black), hydrogen (gray), chlorine (green) 2.33 a b c d e protons and neutrons 11 B 2.35 a b c d e Se group number 6A (16) and period main group element 80 34 Se 2.37 a aluminum b c group number 3A (13) and period 2.39 a iodine 2.16 24 2Mg 25 2Mg 26 2Mg b 1s22s22p63s23p5 2.25 a sodium b silicon c argon a sodium, carbon, nitrogen d tin, fluorines b hydrogens, sulfur e carbon, oxygen c carbons, hydrogens f carbons, hydrogens, oxygens b lithium beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon fluorine oxygen 2.24 a 1s22s22p63s23p1 a hydrogens, carbon b hydrogens, nitrogen c hydrogens, carbons, oxygen a 2.23 a b c d 2.41 a b c d b carbon gold, astatine, silver nitrogen, sodium, nickel sulfur, silicon, tin calcium, chromium, chlorine 2.43 a,c,e: element 2.45 a cesium 2.47 a b c d b,d: compound b ruthenium c chlorine d fluorine sodium: metal, alkali metal, main group element silver: metal, transition metal xenon: nonmetal, noble gas, main group element platinum: metal, transition metal 2.49 Element Atomic Mass Number of Number of Number of Symbol Number Number Protons Neutrons Electrons a b c d C P Zn Mg 15 30 12 12 31 65 24 15 30 12 16 35 12 15 30 12 9/15/10 9:04 AM 67 Answers to Selected Problems 2.51 2.67 a chlorine group 4A b hydrogen, lithium, sodium noble gases 2.69 a 1s22s22p1 2 c carbon b 1s 2s 2p 3s 2.71 a 16 electrons, valence electrons, sulfur b 11 electrons, valence electron, sodium group 10 2.73 An alkali metal has one valence electron and an alkaline earth element has two valence electrons period 2.75 alkaline earth elements Electrons Group Number Valence Electrons Period 20 36 4A 2A 8A 4 a Carbon b Calcium c Krypton transition metals 2.53 hydrogen 2.77 a b c 2.55 K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga: metals Ge, As: metalloids Se, Br, Kr: nonmetals 2.79 a b c 2.57 2.83 a potassium 2.81 a Mass Protons Neutrons Electrons Group Symbol 16 17 18 8 8 10 8 6A 6A 6A 16 8O 17 8O 18 8O 2.59 Protons Neutrons Electrons 13 17 16 14 18 18 13 17 16 a b c 2.61 a 127 53 I b 79 Br 2.63 No, two different elements must have a different number of protons and so, in the neutral atom, they must have a different number of electrons Be 2.85 a silicon b c I d Mg Ar b selenium b chlorine 2.87 fluorine, oxygen, sulfur, silicon, magnesium 2.89 a Cu, group number 1B (11), period b transition metal c 1.0 × 10–6 g 2.91 Sodium Potassium Chlorine a Type b,c: Radius d,e: Ionization Energy f Valence Electrons Metal Metal Nonmetal Largest Smallest Lowest Highest 1 2.93 Strontium is in the same group as calcium, so it has similar chemical properties 2.65 Both the 1s and 2s orbitals are spherical, but the 2s orbital is larger smi11153_ch02_034-067.indd 67 9/15/10 9:04 AM Zinc oxide is an ionic compound widely used in sunblocks to protect the skin from harmful ultraviolet radiation Ionic and Covalent Compounds CHAPTER OUTLINE 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 Introduction to Bonding Ions Ionic Compounds Naming Ionic Compounds Physical Properties of Ionic Compounds Polyatomic Ions Covalent Bonding Lewis Structures Naming Covalent Compounds Molecular Shape Electronegativity and Bond Polarity Polarity of Molecules CHAPTER GOALS In this chapter you will learn how to: ➊ Describe the basic features of ionic and covalent bonds ➋ Use the periodic table to determine the charge of an ion using the group number ➌ ➍ ➎ ➏ ➐ Describe the octet rule ➑ ➒ ❿ ⓫ Draw Lewis structures for covalent compounds Write the formula for an ionic compound Name ionic compounds Describe the properties of ionic compounds Recognize the structures of common polyatomic ions and name compounds that contain them Name covalent compounds that contain two types of elements Predict the shape around an atom in a molecule Use electronegativity to determine whether a bond is polar or nonpolar ⓬ Determine whether a molecule is polar or nonpolar 68 smi11153_ch03_068-104.indd 68 9/17/10 10:47 AM 3.1 Introduction to Bonding 69 Although much of the discussion in Chapter focused on atoms, individual atoms are rarely encountered in nature Instead, atoms are far more commonly joined together to form compounds There are two types of chemical compounds, ionic and covalent Ionic compounds are composed of positively and negatively charged ions held together by strong electrostatic forces—the electrical attraction between oppositely charged ions Examples of ionic compounds include the sodium chloride (NaCl) in table salt and the calcium carbonate (CaCO3) in snail shells Covalent compounds are composed of individual molecules, discrete groups of atoms that share electrons Covalent compounds include water (H2O) and methane (CH4), the main component of natural gas Chapter focuses on the structure and properties of ionic and covalent compounds 3.1 Introduction to Bonding It is rare in nature to encounter individual atoms Instead, anywhere from two to hundreds or thousands of atoms tend to join together to form compounds The oxygen we breathe, for instance, consists of two oxygen atoms joined together, whereas the hemoglobin that transports it to our tissues consists of thousands of carbon, hydrogen, oxygen, nitrogen, and sulfur atoms joined together We say two atoms are bonded together • Bonding is the joining of two atoms in a stable arrangement Only the noble gases in group 8A of the periodic table are particularly stable as individual atoms; that is, the noble gases not readily react to form bonds, because the electronic configuration of the noble gases is especially stable to begin with As a result, one overriding principle explains the process of bonding • In bonding, elements gain, lose, or share electrons to attain the electronic configuration of the noble gas closest to them in the periodic table Bonding involves only the valence electrons of an atom There are two different kinds of bonding: ionic and covalent • Ionic bonds result from the transfer of electrons from one element to another • Covalent bonds result from the sharing of electrons between two atoms The position of an element in the periodic table determines the type of bonds it makes Ionic bonds form between a metal on the left side of the periodic table and a nonmetal on the right side As shown in Figure 3.1, when the metal sodium (Na) bonds to the nonmetal chlorine (Cl2), the ionic compound sodium chloride (NaCl) forms Ionic compounds are composed of ions—charged species in which the number of protons and electrons in an atom is not equal Covalent bonds are formed when two nonmetals combine, or when a metalloid bonds to a nonmetal A molecule is a compound containing two or more atoms joined together with covalent bonds For example, when two hydrogen atoms bond they form the molecule H2, and two electrons are shared hydrogen atoms H H H H + Two electrons are shared in a covalent bond hydrogen molecule smi11153_ch03_068-104.indd 69 9/17/10 10:47 AM 70 Chapter Ionic and Covalent Compounds Sodium metal Figure 3.1 Chlorine gas Sodium chloride crystals Sodium Chloride, an Ionic Compound Na+ (sodium ion) Na Cl2 Cl– (chloride ion) Sodium metal and chlorine gas are both elements Sodium chloride is an ionic compound composed of sodium ions and chloride ions HEALTH NOTE SAMPLE PROBLEM 3.1 Predict whether the bonds in the following compounds are ionic or covalent: (a) NaI (sodium iodide); (b) H2O2 (hydrogen peroxide) Analysis When a metal and nonmetal combine, the bond is ionic When two nonmetals combine, or a metalloid bonds to a nonmetal, the bond is covalent Solution a Since Na is a metal on the left side and I is a nonmetal on the right side of the periodic table, the bonds in NaI are ionic b Since H2O2 contains only the nonmetals hydrogen and oxygen, the bonds must be covalent PROBLEM 3.1 Predict whether the bonds in the following species are ionic or covalent a CO b CaF2 c MgO d Cl2 e HF PROBLEM 3.2 Hydrogen peroxide (Sample Problem 3.1) is used to disinfect wounds Label each of the following as a compound, element, or molecule In some cases, more than one term applies a CO2 3.2 b H2O c NaF d MgBr2 e F2 Ions Ionic compounds consist of oppositely charged ions that have a strong attraction for each other 3.2A Cations and Anions There are two types of ions called cations and anions • Cations are positively charged ions A cation has fewer electrons than protons • Anions are negatively charged ions An anion has more electrons than protons smi11153_ch03_068-104.indd 70 9/17/10 10:47 AM 3.2 71 Ions The charge on an ion depends on the position of an element in the periodic table In forming an ion, an atom of a main group element loses or gains electrons to obtain the electronic configuration of the noble gas closest to it in the periodic table This gives the ion an especially stable electronic arrangement in which the electrons completely fill the shell farthest from the nucleus For example, sodium (group 1A) has an atomic number of 11, giving it 11 protons and 11 electrons in the neutral atom This gives sodium one more electron than neon, the noble gas closest to it in the periodic table In losing one electron, sodium forms a cation with a +1 charge, which still has 11 protons, but now has only 10 electrons in its electron cloud 11 protons 12 neutrons + + + + 11 protons 12 neutrons + + + + + + + + + + + + + + + + + + loss of e− 11 electrons 10 electrons sodium atom sodium cation Na Na+ 1s22s22p63s1 1s22s22p6 electron in the outer shell electrons in the outer shell What does this mean in terms of valence electrons? A neutral sodium atom, with an electronic configuration of 1s22s22p63s1, has a single valence electron Loss of this valence electron forms a sodium cation, symbolized as Na+, which has the especially stable electronic configuration of the noble gas neon, 1s22s22p6 The sodium cation now has eight electrons that fill the 2s and three 2p orbitals Sodium is an example of a metal Some metals—notably tin and lead— can lose four electrons to form cations • Metals form cations By losing one, two, or three electrons, an atom forms a cation with a completely filled outer shell of electrons A neutral chlorine atom (group 7A), on the other hand, has 17 protons and 17 electrons This gives it one fewer electron than argon, the noble gas closest to it in the periodic table By gaining one electron, chlorine forms an anion with a –1 charge because it still has 17 protons, but now has 18 electrons in its electron cloud 17 protons 18 neutrons 17 protons 18 neutrons + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + gain of e− 18 electrons 17 electrons chlorine atom chloride anion Cl Cl 1s22s22p63s23p5 electrons in the outer shell smi11153_ch03_068-104.indd 71 − 1s22s22p63s23p6 electrons in the outer shell 9/17/10 10:47 AM 72 Chapter Ionic and Covalent Compounds In terms of valence electrons, a neutral chlorine atom, with an electronic configuration of 1s22s22p63s23p5, has seven valence electrons Gain of one electron forms a chloride anion, symbolized as Cl–, which has the especially stable electronic configuration of the noble gas argon, 1s22s22p63s23p6 The chloride anion now has eight valence electrons that fill the 3s and three 3p orbitals Chlorine is an example of a nonmetal Ions are written with the element symbol followed by a superscript to indicate the charge The number “1” is omitted in ions that have a +1 or –1 charge, as in Na+ or Cl– When the charge is “2” or greater, it is written as 2+ or 2–, as in Mg2+ or O2– • Nonmetals form anions By gaining one, two, or sometimes three electrons, an atom forms an anion with a completely filled outer shell of electrons Each of these ions formed from a main group element has eight valence electrons This illustrates the octet rule • A main group element is especially stable when it possesses an octet of electrons in its outer shell SAMPLE PROBLEM 3.2 Write the ion symbol for an atom with: (a) nine protons and 10 electrons; (b) three protons and two electrons Analysis Since the number of protons equals the atomic number (Section 2.2), this quantity identifies the element The charge is determined by comparing the number of protons and electrons If the number of electrons is greater than the number of protons, the charge is negative (an anion) If the number of protons is greater than the number of electrons, the charge is positive (a cation) Solution a An element with nine protons has an atomic number of nine, identifying it as fluorine (F) Since there is one more electron than proton (10 vs 9), the charge is –1 Answer: F– b An element with three protons has an atomic number of three, identifying it as lithium (Li) Since there is one more proton than electron (3 vs 2), the charge is +1 Answer: Li+ PROBLEM 3.3 Write the ion symbol for an atom with the given number of protons and electrons a 19 protons and 18 electrons c 35 protons and 36 electrons b seven protons and 10 electrons d 23 protons and 21 electrons SAMPLE PROBLEM 3.3 How many protons and electrons are present in each ion: (a) Ca2+; (b) O2–? Analysis Use the identity of the element to determine the number of protons The charge tells how many more or fewer electrons there are compared to the number of protons A positive charge means more protons than electrons, while a negative charge means more electrons than protons Solution a Ca2+: The element calcium (Ca) has an atomic number of 20, so it has 20 protons Since the charge is +2, there are two more protons than electrons, giving the ion 18 electrons b O2–: The element oxygen (O) has an atomic number of eight, so it has eight protons Since the charge is –2, there are two more electrons than protons, giving the ion 10 electrons PROBLEM 3.4 How many protons and electrons are present in each ion? a Ni2+ smi11153_ch03_068-104.indd 72 b Se2– c Zn2+ d Fe3+ 9/17/10 10:47 AM 3.2 73 Ions 3.2B Relating Group Number to Ionic Charge for Main Group Elements Since elements with similar electronic configurations are grouped together in the periodic table, elements in the same group form ions of similar charge The group number of a main group element can be used to determine the charge on an ion derived from that element • Metals form cations For metals in groups 1A, 2A, and 3A, the group number = the charge on the cation Group 1A elements (Li, Na, K, Rb, and Cs) have one valence electron Loss of this electron forms a cation with a +1 charge Group 2A elements (Be, Mg, Ca, Sr, and Ba) have two valence electrons Loss of both electrons forms a cation with a +2 charge Group 3A elements (Al, Ga, In, and Tl) form cations, too, but only aluminum is commonly found in ionic compounds It has three valence electrons, so loss of three electrons from aluminum forms a cation with a +3 charge • Nonmetals form anions For nonmetals in groups 6A and 7A, the anion charge = – (the group number) Group 6A elements have six valence electrons A gain of two electrons forms an anion with a –2 charge (anion charge = – 6) Group 7A elements have seven valence electrons A gain of one electron forms an anion with a –1 charge (anion charge = – 7) The periodic table in Figure 3.2 gives the common ions formed by the main group elements Figure 3.2 Common Ions Formed by Main Group Elements Group 6A nonmetals form anions with a −2 charge Group 2A metals form cations with a +2 charge 1A 8A 2A 3A Li+ Be2+ Na+ Mg2+ K+ Ca2+ Rb+ Sr2+ Transition metals Al3+ 4A 5A 6A 7A O2− F− S2− Cl− Se2− Br− I− Cs+ Ba2+ Group 1A metals form cations with a +1 charge smi11153_ch03_068-104.indd 73 Halogens form anions with a −1 charge 9/17/10 10:47 AM ... II: Organic Chemistry 312 11 Unsaturated Hydrocarbons 11 .1 11. 2 11 .3 11 .4 11 .5 11 .6 11 .7 11 .8 11 .9 11 .10 smi 111 53_FM_i-xxii.indd viii 322 Alkenes and Alkynes 323 Nomenclature of Alkenes and Alkynes... Atomic Number 10 93 28 41 102 76 46 15 78 94 84 19 59 61 91 88 86 75 45 11 1 37 44 10 4 62 21 106 34 14 47 11 38 16 73 43 52 65 81 90 69 50 22 74 92 23 54 70 39 30 40 11 2** 11 3 11 4 11 5 11 6 11 8 Relative... 12 . 011 14 .0067 15 .9994 18 .9984 20 .17 97 Cu 10 1.07 10 2.9055 10 6.42 10 7.8682 11 2. 411 10 4 Fr 10 5 44 Ru 89 (223) Co 10 1B 11 50.9 415 51. 99 61 54.9380 55.845 58.9332 58.693 88.9059 91. 224 92.9064 13 2.9054