Chemistry Lecture Notes - Atoms, Molecules, and Ions - PDF

Chemistry Eighth Edition Chapter 2 Atoms, Molecules, and Ions Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Chemistry and the Elements (1 of 2) Table 2.1 Names and Symbols of Some C...

Chemistry Eighth Edition Chapter 2 Atoms, Molecules, and Ions Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Chemistry and the Elements (1 of 2) Table 2.1 Names and Symbols of Some Common Elements. Latin names from which the symbols of some elements are derived are shown in parentheses. Element Symbol Aluminum Al Argon Ar Barium Ba Boron B Bromine Br Calcium Ca Carbon C Chlorine Cl Fluorine F Helium He Hydrogen H Iodine I Lithium Li Magnesium Mg Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Chemistry and the Elements (2 of 2) Table 2.1 Names and Symbols of Some Common Elements. Latin names from which the symbols of some elements are derived are shown in parentheses. Element Symbol Manganese Mn Nitrogen N Oxygen O Phosphorus P Silicon Si Sulfur S Zinc Zn Copper (cuprum) Cu Iron (ferrum) Fe Lead (plumbum) Pb Mercury (hydrargyrum) Hg Potassium (kalium) K Silver (argentum) Ag Sodium (natrium) Na Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Figure 2.3 Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Elements and the Periodic Table (1 of 2) Periods: 7 horizontal rows Groups: 18 vertical columns – International standard: 1–18 – U.S. system: 1A–8A, 1B–8B Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Elements and the Periodic Table (2 of 2) Main Groups – Columns 1A–2A (2 groups) – Columns 3A–8A (6 groups) Transition Metals: 3B–2B (8 groups, 10 columns) Inner Transition Metals: 14 groups between 3B and 4B – Lanthanides – Actinides Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (1 of 9) Intensive Properties: Independent of sample size – Temperature – Melting point Extensive Properties: Dependent on sample size – Length – Volume Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (2 of 9) Physical Properties: Characteristics that do not involve a change in a sample’s chemical makeup Chemical Properties: Characteristics that do involve a change in a sample’s chemical makeup Table 2.3 Some Examples of Physical Odor and Chemical Properties Solubility Hardness Physical Properties Temperature Chemical Properties Color Rusting (of iron) Melting point Combustion (of gasoline) Electrical conductivity Tarnishing (of silver) Amount Cooking (of an egg) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (3 of 9) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (4 of 9) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (5 of 9) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (6 of 9) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (7 of 9) Metals: Left side of the zigzag line in the periodic table (except for hydrogen) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (8 of 9) Nonmetals: Right side of the zigzag line in the periodic table Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Some Common Groups of Elements and Their Properties (9 of 9) Semimetals (metalloids): Tend to lie along the zigzag line in the periodic table Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Observations Supporting Atomic Theory: The Conservation of Mass and the Law of Definite Proportions (1 of 3) Law of Conservation of Mass: Mass is neither created nor destroyed in chemical reactions. Aqueous solutions of mercury (II) nitrate and potassium iodide will react to form a precipitate of mercury (II) iodide and aqueous potassium iodide. 3.25g  3.32g 6.57g             Hg(NO3 )2 (aq )  2Kl(aq ) Hgl (s )  2KNO (aq )   2      3   4.55g+2.02g=6.57g Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Observations Supporting Atomic Theory: The Conservation of Mass and the Law of Definite Proportions (2 of 3) Known amounts of solid The solutions are The solution that remains is KI and solid Hg(NO3 )2 mixed to give solid evaporated to give solid KNO3. are weighed and then Hgl2 , which is On weighing, the combined masses dissolved in water. removed by filtration. of the products equal the combined masses of the reactants. 3.25g  3.32g 6.57g             Hg(NO3 )2 (aq )  2Kl(aq ) Hgl (s )  2KNO (aq )   2      3   4.55g+2.02g=6.57g Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Observations Supporting Atomic Theory: The Conservation of Mass and the Law of Definite Proportions (3 of 3) Law of Definite Proportions: Different samples of a pure chemical substance always contain the same proportion of elements by mass. By mass, water is 88.8% oxygen 11.2% hydrogen Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved The Law of Multiple Proportions and Dalton’s Atomic Theory (1 of 4) Law of Multiple Proportions: Elements can combine in different ways to form different substances, whose mass ratios are small whole-number multiples of each other. Nitrogen monoxide: 7 grams nitrogen per 8 grams oxygen Nitrogen dioxide: 7 grams nitrogen per 16 grams oxygen Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved The Law of Multiple Proportions and Dalton’s Atomic Theory (2 of 4) Law of Multiple Proportions: Elements can combine in different ways to form different substances, whose mass ratios are small whole- number multiples of each other. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved The Law of Multiple Proportions and Dalton’s Atomic Theory (3 of 4) Elements are made up of tiny particles called atoms. Each element is characterized by the mass of its atoms. Atoms of the same element have the same mass, but atoms of different elements have different masses. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved The Law of Multiple Proportions and Dalton’s Atomic Theory (4 of 4) The chemical combination of elements to make different chemical compounds occurs when atoms join in small whole-number ratios. Chemical reactions only rearrange how atoms are combined in chemical compounds; the atoms themselves don’t change. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Structure: Electrons (1 of 2) Cathode-Ray Tubes: J. J. Thomson (1856–1940) proposed that cathode rays must consist of tiny, negatively charged particles. We now call them electrons. (a) The electron beam ordinarily travels in a (b) The beam is deflected by either a straight line. magnetic field or an electric field. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Structure: Electrons (2 of 2) Cathode-Ray Tubes: J. J. Thomson (1856–1940) proposed that cathode rays must consist of tiny, negatively charged particles. We now call them electrons. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Structure: Protons and Neutrons (1 of 5) Atomic Nucleus: Ernest Rutherford (1871–1937) bombarded gold foil with alpha particles. Although most of the alpha particles passed through the foil undeflected, approximately 1 in every 20,000 particles was deflected. A fraction of those particles were deflected back at an extreme angle. Rutherford proposed that the atom must consist mainly of empty space, with the mass concentrated in a tiny central core—the nucleus. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Structure: Protons and Neutrons (2 of 5) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Structure: Protons and Neutrons (3 of 5) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Structure: Protons and Neutrons (4 of 5) Table 2.4 A Comparison of Subatomic Particles Blank Mass Mass Charge Charge Particle Grams u* Coulombs e Electron 9.109382 10  28 5.485799 10  4  1.602176 10  19 −1 9.109382 times 10 to the power of minus 28 5.485799 times 10 to the power of minus 4. Minus 1.602176 times 10 to the power of minus 19 Proton 1.672622 10  24 1.007276 1.602176 10  19 +1 1.672622 times 10 to the power of minus 24 1.007276 Plus 1.602176 times 10 to the power of minus 19 Neutron 1.674927 10  24 1.008665 0 0 1.674927 times 10 to the power of minus 24 1.008665 *The unified atomic mass unit (u) is defined in Section 2.9. The mass of the atom is primarily in the nucleus. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Structure: Protons and Neutrons (5 of 5) Table 2.4 A Comparison of Subatomic Particles Blank Mass Mass Charge Charge Particle Grams u* Coulombs e Electron 9.109382 10  28 5.485799 10  4  1.602176 10  19 −1 9.109382 times 10 to the power of minus 28 5.485799 times 10 to the power of minus 4 Minus 1.602176 times 10 to the power of minus 19 Proton 1.672622 10  24 1.007276 1.602176 10  19 +1 1.672622 times 10 to the power of minus 24 1.007276 Plus 1.602176 times 10 to the power of minus 19 Neutron 1.674927 10  24 1.008665 0 0 1.674927 times 10 to the power of minus 24 1.008665 *The unified atomic mass unit (u) is defined in Section 2.9. The charge of the proton is opposite in sign but equal to that of the electron. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Numbers (1 of 3) Atomic Number (Z): Number of protons in an atom’s nucleus, equivalent to the number of electrons around an atom’s nucleus Mass Number (A): The sum of the number of protons and the number of neutrons in an atom’s nucleus Isotope: Atoms with identical atomic numbers but different mass numbers Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Numbers (2 of 3) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Numbers (3 of 3) Carbon-12: Carbon-14: Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Weights and the Mole The mass of 1 atom of carbon-12 is defined to be 12 a m u. tomic ass nit Atomic Weight: The weighted average of the isotopic masses of the element’s naturally occurring isotopes Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Masses and the Mole (1 of 2) Why is the atomic weight of the element carbon 12.01 amu? Carbon-12: 98.89% natural abundance 12 a m u tomic ass nit Carbon-13: 1.11% natural abundance 13.0034 amu Mass of carbon (12 amu) 0.9889   (13.0034amu ) 0.0111 11.87 amu  0.144 amu 12.01 amu Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Atomic Masses and the Mole (2 of 2) Avogadro’s Number (NA ): One mole of any substance contains 6.022 1023 formula units. Molar Mass: It is the mass in grams of one mole of any element. It is numerically equivalent to its atomic weight. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Measuring Atomic Weight: Mass Spectrometry (1 of 2) The most common method of measuring an element’s atomic weight is with an instrument called a mass spectrometer. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Measuring Atomic Weight: Mass Spectrometry (2 of 2) Mass spectrum of a sample of boron Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Mixtures and Chemical Compounds; Molecules and Covalent Bonds (1 of 4) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Mixtures and Chemical Compounds; Molecules and Covalent Bonds (2 of 4) Covalent Bond: Results when two atoms share several (usually two) electrons. Typically a nonmetal bonded to a nonmetal. The two teams are joined together because both are tugging on the same rope. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Mixtures and Chemical Compounds; Molecules and Covalent Bonds (3 of 4) Covalent Bond: It results when two atoms share several (usually two) electrons. It is typically a nonmetal bonded to a nonmetal. Molecule: It is the unit of matter that results when two or more atoms are joined by covalent bonds. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Mixtures and Chemical Compounds; Molecules and Covalent Bonds (4 of 4) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Ions and Ionic Bonds (1 of 4) Ionic Bond: It is a transfer of one or more electrons from one atom to another. A strong electrical attraction between charged particles creates Ionic bonds. It is typically a metal bonded to a nonmetal. Ion: A charged particle Cation: It is a positively charged particle. Metals tend to form cations. Anion: It is a negatively charged particle. Nonmetals tend to form anions. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Ions and Ionic Bonds (2 of 4) In the formation of sodium chloride, one electron is transferred from the sodium atom to the chlorine atom. 1 Na  Cl2 Na   Cl 2 Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Ions and Ionic Bonds (3 of 4) Cation Charges for Typical Main-Group Ions Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Ions and Ionic Bonds (4 of 4) Anion Charges for Typical Main-Group Ions Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (1 of 10) Ionic Compound: It is a neutral compound in which the total number of positive charges must equal the total number of negative charges. Binary Ionic Compounds Sodium chloride: Na  Cl NaCl Magnesium oxide: Mg2 O2 MgO Aluminum sulfide: Al3  S2– Al2S3 Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (2 of 10) Some transition metals form more than one cation. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (3 of 10) Use Roman numerals in parentheses to indicate the charge on metals that form more than one kind of cation. Binary Ionic Compounds Iron (III) oxide: Fe3  O2 Fe2O3 Tin (II) chloride: Sn2 Cl SnCl2 Lead (II) fluoride: Pb2 F– PbF2 Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (4 of 10) Table 2.5 Some Common Polyatomic Ions Formula Name Cation Cation NH4  N H subscript 4 baseline superscript plus Ammonium Singly charged anions Singly charged anions CH3CO2  C H subscript 3 C O subscript 2 baseline superscript minus. Acetate CN C N superscript minus Cyanide ClO C l O superscript minus Hypochlorite ClO2  C l O subscript 2 baseline superscript minus Chlorite ClO3  C l O subscript 3 baseline superscript minus Chlorate ClO4  C I O subscript 4 baseline superscript minus Perchlorate H2PO4  H subscript 2 P O subscript 4 baseline superscript minus Dihydrogen phosphate HCO3  H C O subscript 3 baseline superscript minus Hydrogen carbonate (or bicarbonate) Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (5 of 10) Table 2.5 Some Common Polyatomic Ions Formula Name HSO4  H S O subscript 4 baseline superscript minus Hydrogen sulfate (or bisulfate) OH O H superscript minus Hydroxide MnO4  M n O subscript 4 baseline superscript minus Permanganate NO2  N O subscript 2 baseline superscript minus Nitrite NO3  N O subscript 3 baseline superscript minus Nitrate Doubly charged anions Doubly charged anions CO3 2 C O subscript 3 baseline superscript 2 minus Carbonate CrO4 2 C r O subscript 4 baseline superscript 2 minus Chromate Cr2O7 2 C r subscript 2 O subscript 7 baseline superscript 2 minus Dichromate O 2 2 O subscript 2 baseline superscript 2 minus Peroxide HPO4 2 H P O subscript 4 baseline superscript 2 minus Hydrogen phosphate Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (6 of 10) Table 2.5 Some Common Polyatomic Ions Formula Name SO3 2 S O subscript 3 baseline superscript 2 minus Sulfite Sulfate SO4 2 S O subscript 4 baseline superscript 2 minus S2O3 2 S subscript 2 O subscript 3 baseline superscript 2 minus Thiosulfate Triply charged anion Triply charged anion PO43 P O subscript 4 baseline superscript 3 minus Phosphate Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (7 of 10) Polyatomic Ionic Compounds Sodium hydroxide: Na  OH NaOH Magnesium carbonate: Mg2 CO3 2– MgCO3 Sodium carbonate: Na  CO3 2– Na2CO3 Iron (II) hydroxide: Fe2 OH Fe OH2 Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (8 of 10) Binary Molecular Compounds Table 2.6 Numerical Prefixes for Naming Compounds Prefix Meaning mono- 1 di- 2 Because nonmetals often tri- 3 combine with one another in tetra- 4 different proportions to form penta- 5 different compounds, hexa- 6 numerical prefixes are usually hepta- 7 included in the names of octa- 8 binary molecular compounds. nona- 9 deca- 10 Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (9 of 10) N2F4 The prefix is added to the front of each name to indicate the number of each atom. Dinitrogen tetrafluoride Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Naming Chemical Compounds (10 of 10) Binary Molecular Compounds Whenever the prefix ends in a or o and the element name begins with a vowel, drop the a or o in the prefix. N2O4 Dinitrogen tetroxide Whenever the prefix for the first element is mono-, drop it. CO2 Carbon dioxide C O Carbon monoxide Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved Copyright This work is protected by United States copyright laws and is provided solely for the use of instructors in teaching their courses and assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work and is not permitted. The work and materials from it should never be made available to students except by instructors using the accompanying text in their classes. All recipients of this work are expected to abide by these restrictions and to honor the intended pedagogical purposes and the needs of other instructors who rely on these materials. Copyright © 2020, 2016, 2012 Pearson Education, Inc. All Rights Reserved