Chapter 3: Elements, Compounds, and the Periodic Table PDF

Chapter 3: Elements, Compounds, and the Periodic Table Chemistry: The Molecular Nature of Matter, 6E Jespersen/Brady/Hyslop  Atomic Structure  Electrons (e)  Very low mass  Occupy most of atom’s space  Balance of attractive & repulsive...

Chapter 3: Elements, Compounds, and the Periodic Table Chemistry: The Molecular Nature of Matter, 6E Jespersen/Brady/Hyslop  Atomic Structure  Electrons (e)  Very low mass  Occupy most of atom’s space  Balance of attractive & repulsive forces controls atom size  Attraction between protons (p+) & electrons (e) holds electrons around nucleus  Repulsion between electrons helps them spread out over volume of atom  In neutral atom  Number of es must equal number of p+s  Diameter of atom ~10,000 × diameter of nucleus Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 2 Properties of Subatomic Particles Nucleus (protons  3 Kinds of subatomic + neutrons) particles of principal interest to Chemists Electrons Electrical Particle Mass (g) Symbol Charge 0 Electron 9.109391028 1 1 e 1 1 Proton 1.672641024 +1 1 H, 1 p Neutron 1.674951024 0 1 0n Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 3  Atomic Notation Atomic number (Z)  Number of protons that atom has in nucleus  Unique to each type of element  Element is substance whose atoms all contain identical number of protons  Z = # protons Isotopes  Atoms of same element with different masses  Same number of protons (11 p )  Different number of neutrons (10n ) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 4  Atomic Notation Mass number (A)  A = (# protons) + (# neutrons)  A=Z+N  For charge neutrality, number of electrons & protons must be equal Atomic Symbols  Summarize information about subatomic particles  Every isotope defined by 2 numbers Z & A A  Symbolized by X Z Ex. What is the atomic symbol for helium? 4 He has 2 e–, 2n&2 p+ Z = 2, A = 4 2 He Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 5  Isotopes  Most elements are mixtures of 2 or more stable isotopes  Each isotope has slightly different mass  Chemically, isotopes have virtually identical chemical properties  Isotopes distinguished by mass number (A): Ex.  3 isotopes of hydrogen (H)  4 isotopes of iron (Fe) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 6  7 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E  Example: What is the isotopic symbol for Uranium- 235?  Number of protons (p+) = 92 = number of electrons in neutral atom  Number of neutrons (1n) = 143  Atomic number (Z) = 92  Mass number (A) = 92 + 143 = 235  Chemical symbol = U  Summary for uranium-235: 235 92 U Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 8  Your Turn! 206 An atom of Pb has ___ protons, ___ 82 neutrons, and ___ electrons. A. 82, 206, 124 B. 124, 206, 124 C. 124, 124, 124 D. 82, 124, 82 E. 82, 124, 124 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 9  Calculating Atomic Mass  Generally, elements are mixtures of isotopes Ex. Hydrogen Isotope Mass %Abundance 1H 1.007825 u 99.985 2H 2.0140 u 0.015 How do we define Atomic Mass?  Average of masses of all stable isotopes of given element How do we calculate Average Atomic Mass?  Weighted average.  Use Isotopic Abundances & isotopic masses Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 10  Learning Check Naturally occurring magnesium is a mixture of 3 isotopes; 78.99% of the atoms are 24Mg (atomic mass, 23.9850 u), 10.00% of 25Mg (atomic mass, 24.9858 u), and 11.01% of 26Mg (atomic mass, 25.9826 u). From these data calculate the average atomic mass of magnesium. 0.7899 * 23.9850 u = 18.946 u 24Mg 0.1000 * 24.9858 u = 2.4986 u 25Mg 0.1101 * 25.9826 u = 2.8607 u 26Mg Total mass of average atom = 24.3053 u rounds up to 24.31 u Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 11  Your Turn! A naturally occurring element consists of two isotopes. The data on the isotopes: isotope #1 68.5257 u 60.226% isotope #2 70.9429 u 39.774% Calculate the average atomic mass of this element. A.70.943 u 0.60226 * 68.5257 u = 41.270 u B.69.487 u 0.39774 * 70.9429 u = 28.217 u C.69.526 u 69.487 u D.69.981 u E.69.734 u Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 12  Periodic Table  Summarizes periodic properties of elements Early Versions of Periodic Tables  Arranged by increasing atomic mass  Mendeleev (Russian) & Meyer (German) in 1869 Modern Periodic Table  Arranged by increasing atomic number (Z):  Rows called periods  Columns called groups or families  Identified by numbers  1 – 18 standard international  1A – 8A longer columns & 1B – 8B shorter columns Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 13  Modern Periodic Table with group labels and chemical families identified Actinides Note: Placement of elements 58 – 71 and 90 – 103 saves space Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 14 Representative/Main Group Elements A groups—Longer columns  Alkali Metals  1A = first group  Very reactive  All Metals except for H  Tend to form +1 ions  React with oxygen  Form compounds that dissolve in water  Yield strongly caustic or alkaline solution (M2O) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 15 Representative/Main Group Elements A groups—Longer columns  Alkaline Earth Metals  2A = second group  Reactive  Tend to form +2 ions  Oxygen compounds are strongly alkaline (MO)  Many are not water soluble  Accumulate in ground Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 16 Representative/Main Group Elements A groups—Longer columns  Halogens  7A = next to last group on right  Reactive  Form diatomic molecules in elemental state  2 gases  1 liquid  2 solids  Form –1 ions with alkali metals—salts Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 17 Representative/Main Group Elements A groups—Longer columns  Noble Gases  8A = last group on right  Inert—very unreactive  Don’t form charged ions  Monatomic gases Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 18  Transition Elements B groups—shorter columns  All are metals  In center of table  Begin in fourth row  Tend to form ions with several different charges Ex.  Fe2+ and Fe3+  Cu+ and Cu2+  Mn2+, Mn3+, Mn4+, Mn5+, Mn6+, Mn7+ Note: Last 3 columns all have 8B designation Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 19  Inner Transition Elements Lanthanide elements  Elements 58 – 71 Actinide elements  Elements 90 – 103  At bottom of periodic table  Tend to form +2 and +3 ions.  All Actinides are radioactive Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 20  Metals, Nonmetals, or Metalloids  Elements break down into 3 broad categories  Organized by regions of periodic table Metals  Left-hand side  Sodium, lead, iron, gold Nonmetals  Upper right hand corner  Oxygen, nitrogen, chlorine Metalloids  Diagonal line between metals & nonmetals  Boron to astatine Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 21  Metals, Nonmetals, or Metalloids Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 22  Metals  Most elements in periodic table Properties  Metallic luster  Shine or reflect light  Malleable  Can be hammered or rolled into thin sheets  Ductile  Can be drawn into wire  Hardness  Some hard – iron & chromium  Some soft – sodium, lead, copper Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 23  Properties of Metals  Conduct heat & electricity  Solids at Room Temperature  Melting points (mp) > 25 °C  Hg only liquid metal (mp = –39 °C)  Tungsten (W) (mp = 3400 °C)  Highest known for metal  Chemical reactivity  Varies greatly  Au, Pt very unreactive  Na, K very reactive Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 24  Nonmetals  17 elements  Upper right hand corner of periodic table  Exist mostly as compounds rather than as pure elements  Many are Gases  Monatomic (Noble) He, Ne, Ar, Kr, Xe, Rn  Diatomic H2, O2, N2, F2, Cl2  Some are Solids: I2, Se8, S8, P4, C  3 forms of Carbon (graphite, coal, diamond)  One is liquid: Br2 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 25  Properties of Nonmetals  Brittle  Pulverize when struck  Insulators  Non-conductors of electricity and heat  Chemical reactivity  Some inert  Noble gases  Some reactive  F2, O2, H2  React with metals to form ionic compounds Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 26  Metalloids  8 Elements  Located on diagonal line between metals & nonmetals  B, Si, Ge, As, Sb, Te, Po, At Properties  Between metals & nonmetals  Metallic shine  Brittle like nonmetal  Semiconductors  Conduct electricity  But not as well as metals  Silicon (Si) & germanium (Ge) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 27  Ions & Ionic Compounds Ions  Transfer of 1 or more electrons from 1 atom to another  Form electrically charged particles Ionic compound  Compound composed of ions  Formed from metal & nonmetal  Infinite array of alternating Na+ & Cl ions Formula unit  Smallest neutral unit of ionic compound  Smallest whole-number ratio of ions Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 28  Formation of Ionic Compounds Metal + Non-metal  ionic compound 2Na(s) + Cl2(g)  2NaCl(s) +  Na + Cl Na + Cl NaCl(s) e Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 29  Ionic Compounds Cations  Positively charged ions  Formed from metals  Atoms lose electrons Ex. Na has 11 e– & 11 p+ Na+ has 10 e– & 11 p+ Anions  Negatively charged ions  Formed from non-metals  Atoms gain electrons Ex. Cl has 17 e– & 17 p+ Cl– has 18 e– & 17 p+ Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 30  Experimental Evidence for Ions Electrical conductivity requires charge movement Ionic compounds:  Do not conduct electricity in solid state  Do conduct electricity in liquid & aqueous states where ions are free to move Molecular compounds:  Do not conduct electricity in any state  Molecules are comprised of uncharged particles Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 31  Ions of Representative Elements  Can use periodic table to predict ion charges  When we use North American numbering of groups: Cation positive charge = group # Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 32  Ions of Representative Elements  Noble gases are especially stable Nonmetals  Negative () charge on anion = # spaces you have to move to right to get to noble gas  Expected charge on O is  Move 2 spaces to right N O F Ne  O2–  What is expected charge on N?  Move 3 spaces to right  N3 – Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 33  Rules For Writing Ionic Formulas 1. Cation given first in formula 2. Subscripts in formula must produce electrically neutral formula unit 3. Subscripts must be smallest whole numbers possible  Divide by 2 if all subscripts are even  May have to repeat several times 4. Charges on ions not included in finished formula unit of substance  If no subscript, then 1 implied Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 34  Determining Ionic Formulas Ex. Formula of ionic compound formed when magnesium reacts with oxygen  Mg is group 2A  Forms +2 ion or Mg2+  O is group 6A  Forms –2 ion or O2–  To get electrically neutral particle need  1:1 ratio of Mg2+ & O2–  Formula: MgO Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 35  Determining Ionic Formulas “Criss-cross” rule  Make magnitude of charge on one ion into subscript for other  When doing this, make sure that subscripts are reduced to lowest whole number. Ex. What is the formula of ionic compound formed between aluminum & oxygen ions? Al3+ O2– Al2O3 36 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E  Your Turn! Which of the following is the correct formula for the formula unit composed of potassium and oxygen ions? A.KO B.KO2 C.K2O D.P2O3 E.K2O2 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E  Your Turn! Which of the following is the correct formula for the formula unit composed of Fe3+ and sulfide ions? A.FeS B.Fe3S2 C.FeS3 D.Fe2S3 E.Fe4S6 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E  Cations of Transition Metals Transition metals  Center (shorter) region of periodic table  Much less reactive than group 1A & 2A  Still transfer electrons to nonmetals to form ionic compounds  # of electrons transferred less clear  Form more than 1 positive ion  Can form more than 1 compound with same non-metal Ex. Fe + Cl FeCl2 & FeCl3 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 39  Cations of Post-transition Metals Post-transition metals  9 metals Ga, In, Sn, Tl, Pb, Bi, Uut, Uuq, Uub  After transition metals & before metalloids  2 very important ones – tin (Sn) & lead (Pb)  Both have 2 possible oxidation states  Both form 2 compounds with same nonmetal Ex. Ionic compounds of tin & oxygen are  SnO & SnO2  Bismuth  Only has +3 charge  Bi3+ Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 40  Ions of Some Transition Metals & Post-transition Metals Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 41  Compounds with Polyatomic Ions Binary compounds  Compounds formed from 2 different elements Polyatomic ions  Ions composed of 2 or more atoms linked by molecular bonds  If ions are negative, they have too many electrons  If ions are positive, they have too few electrons  Formulas for ionic compounds containing polyatomic ions  Follow same rules as ionic compounds  Polyatomic ions are expressed in parentheses Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 42  Table 3.4 Polyatomic Ions (Alternate Name in parentheses) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 43  Learning Check Ex. What is the formula of the ionic compound formed between ammonium and phosphate ions?  Ammonium = NH4+  Phosphate = PO43– (NH4)+ (PO4)3– (NH4)3PO4 Ex. Between strontium ion and nitrate ion?  Strontium = Sr2+  Nitrate = NO32– Sr2+ (NO3)– Sr(NO3)2 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 44  Nomenclature (Naming)  IUPAC system to standardize name of chemical compounds  One system so that anyone can reconstruct formula from name  We will look at naming Ionic Compounds of  Representative metals  Transition metals  Monatomic ions  Polyatomic ions  Hydrates Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 45  Naming Ionic Compounds Cations:  Metal that forms only 1 positive ion  Cation name = English name for metal  Na+ sodium  Ca2+ calcium  Metal that forms more than 1 positive ion  Use Stock System  Cation name = English name followed by numerical value of charge written as Roman numeral in parentheses (no spaces)  Transition metal  Cr2+ chromium(II) Cr3+ chromium(III) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 46  Naming Ionic Compounds Anions:  Monatomic anions named by adding “–ide” suffix to stem name for element  Polyatomic ions use names in Table 3.5 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 47  Learning Check: Name The Following  K2O potassium oxide  NH4ClO3 ammonium chlorate  Mg(C2H3O2)2 magnesium acetate  Cr2O3 chromium(III) oxide  ZnBr2 zinc bromide Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 48  Learning Check: Determine The Formula  Calcium hydroxide  Ca(OH)2  Manganese(II) bromide  MnBr2  Ammonium phosphate  (NH4)3PO4  Mercury(I) nitride  (Hg2)3N2 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 49  Your Turn! Which is the correct name for Cu2S? A. copper sulfide B. copper(II) sulfide C. copper(II) sulfate D. copper(I) sulfide E. copper(I) sulfite Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E  Your Turn! Which is the correct formula for ammonium sulfite? a) NH4SO3 b) (NH4)2SO3 c) (NH4)2SO4 d) NH4S e) (NH4)2S Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 51  Naming Hydrates  Ionic compounds  Crystals contain water molecules  Fixed proportions relative to ionic substance  Naming  Name ionic compound  Give number of water molecules in formula using Greek prefixes mono- = 1 hexa- = 6 di- = 2 hepta- = 7 tri- = 3 octa- = 8 tetra- = 4 nona- = 9 penta- = 5 deca- = 10 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 52  Learning Check: Naming Hydrates  CaSO4 · 2H2O  calcium sulfate dihydrate  CoCl2 · 6H2O  cobalt(II) chloride hexahydrate  FeI3 · 3H2O  iron(III) iodide trihydrate Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 53  Your Turn! What is the correct formula for copper(II) sulfate pentahydrate? A.CuSO4 · 6H2O B.CuSO3 · 5H2O C.CoSO4 · 4H2O D.CoSO3 · 5H2O E.CuSO4 · 5H2O Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 54  Molecular Compounds Molecules  Electrically neutral particle  Consists of two or more atoms Chemical bonds  Attractions that hold atoms together in molecules  Arise from sharing electrons between 2 atoms  Group of atoms that make up molecule behave as single particle Molecular formulas  Describe composition of molecule  Specify # of each type of atom present Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 55  Molecules vs. Ionic Compounds Molecules  Discrete unit  Water = 2 hydrogen atoms bonded to 1 oxygen atom Ionic Compounds  Ions packed as close as possible to each other  Sodium chloride = Each cation has 6 anions; each anion has 6 cations Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 56  Molecular Compounds  Formed when nonmetals combine  C + O2  CO2 2H2 + O2  2H2O  Millions of compounds can form from a few non- metals  Organic chemistry & Biochemistry  Deal with chemistry of carbon + H, N & O  A few compounds have only 2 atoms  Diatomics: H2, O2, Cl2, HF, NO  Most molecules are far more complex  Sucrose (C12H22O11) urea (CON2H4) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 57 Hydrogen-containing Compounds Nonmetal hydrides  Molecule containing nonmetal + hydrogen  Number of hydrogens that combine with nonmetal = number of spaces from nonmetal to noble gas in periodic table N O F Ne Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 58  3-D Shapes of Molecules  Space filling models  Used to give shapes of simple nonmetal hydrides  Blue = nitrogen  Red = water  Yellow = fluorine  White = hydrogen Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 59  Organic Compounds  Carbon compounds  Carbon + hydrogen, oxygen, & nitrogen  Originally thought these compounds only came from living organisms  Now more general Hydrocarbons  Simplest organic compounds  Contain only C & H  Always have ratio of atoms CnH2n+2  Named using prefix designating number of C atoms  All have –ane suffix Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 60  Table Hydrocarbons Belonging to the 3.8 Alkane Series Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 61  Alkanes  Boiling point increases as number of carbon atoms increases  Space filling models of alkanes  Black = carbon  White = hydrogen Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 62  Your Turn! Which is the correct name for C4H10? A. methane B. ethane C. propane D. pentane E. butane Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E  Other Hydrocarbons Alkenes  Hydrocarbons with two less H’s than alkanes  CnH2n  Name = number prefix + ene Ex. C2H4 = ethene (ethylene) Alkynes  Hydrocarbons with four fewer H’s than alkanes  CnH2n – 2  Name = number prefix + ene Ex. C2H2 = ethyne (acetylene) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 64  Other Organic Compounds  Hydrocarbons are basic building blocks of organic chemistry  Many other classes of compounds derived from them Alcohols  Replace H in alkane with -OH group  Name = number prefix + anol Ex. CH3OH = methanol (methyl alcohol) C2H5OH = ethanol (ethyl alcohol) Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 65  Your Turn! What is the name of C4H9OH? A. hexanol B. propanol C. pentanol D. tetranol E. butanol Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E  Writing Formulas for Organic Compounds Molecular formula  Indicates # of each type of atom in molecule Ex. C2H6 for ethane or C3H8 for propane  Order of atoms  Carbon | Hydrogen | Other atoms alphabetically Ex. sucrose is C12H22O11 Emphasize alcohol – write OH group last  C2H5OH Structural formula  Indicate how carbon atoms are connected  Ethane = CH3CH3  Propane = CH3CH2CH3 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 67  Your Turn! Octane is a hydrocarbon with 8 C atoms that is the major component of gasoline. What is the correct molecular formula for octane? A. C8H14 B. C8H16 C. C8H18 D. C8H17OH E. C8H15OH Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 68  Your Turn! What is the correct structural formula for octane? a)CH3CH2CH2CH2CH2CH2CH2CH3 b)CH3CH2CH2CH2CH2CH2CH3 c)C8H18 d)CH3CH2CH2CH2CH2CH2CH2CH2CH3 e)CH3CH2CH2CH2CH2CH2CH2CH2OH Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 69  Nomenclature of Molecular Compounds  Goal is a name that translates clearly into molecular formula Naming Binary Molecular Compounds  Which 2 elements present?  How many of each? Format:  First element in formula  Use English name  Second element  Use stem & append suffix –ide  Use Greek number prefixes to specify how many atoms of each element Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 70 Naming Binary Molecular Compounds 1. hydrogen chloride 1 H 1 Cl HCl 2. phosphorous pentachloride 1 P 5Cl PCl5 3. triselenium dinitride 3 Se 2N Se3N2  Mono always omitted on 1st element  Often omitted on 2nd element unless more than one combination of same 2 elements Ex. Carbon monoxide CO Carbon dioxide CO2  When prefix ends in vowel similar to start of element name, drop prefix vowel Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 71  Learning Check: Name Each Format:  Number prefix + 1st element name  Number prefix + stem + –ide for 2nd element  AsF3 = arsenic trifluoride  HBr = hydrogen bromide  N2O4 = dinitrogen tetroxide  N2O5 = dinitrogen pentoxide  CO = carbon monoxide  CO2 = carbon dioxide Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 72  Your Turn! Which is the correct formula for nitrogen triiodide? A.N3I B.NI3 C.NIO3 D.N(IO3)3 E.none of the above Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E  Your Turn! Which is the correct name for P4O10? A. phosphorus oxide B. phosphorous decoxide C. tetraphosphorus decoxide D. tetraphosphorus oxide E. decoxygen tetraphosphide Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E Exceptions to Naming Binary Molecules Binary compounds of nonmetals + hydrogen  No prefixes to be used  Get number of hydrogens for each nonmetal from periodic table  Hydrogen sulfide = H2S  Hydrogen telluride = H2Te Molecules with Common Names  Some molecules have names that predate IUPAC systematic names  Water H 2O ▪ Sucrose C12H22O11  Ammonia NH3 ▪ Phosphine PH3 Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 75  Summary of Naming Jespersen/Brady/Hyslop Chemistry: The Molecular Nature of Matter, 6E 76