Nomenclature

Objectives write formulas for ionic compounds name ionic compounds write formulas for simple covalent compounds name simple covalent compounds

Classification of Matter

Compounds Pure substances Formed when 2 or more elements are chemically bound in a fixed ratio There are millions of different compounds made from the ~100 elements

How do we Represent or Model Compounds? Macroscopic: large scale -what you can see Submicroscopic: small scale- cannot see- need a model Chemical formula H 2 O

Chemical formulas Combination of chemical symbols that represents the composition of a compound  indicates the elements present  indicates the relative number (how many) of each element in the compound

X charge number of atoms mass number atomic number PbS 2 Chemical symbols

How many of each type of atom? C 3 H 8 propane NaClsalt NaHCO 3 baking soda Fe 2 O 3 rust C 12 H 22 O 11 sugar C 9 H 8 O 4 aspirin Mg(OH) 2 magnesium hydroxide

Compounds Covalent(Molecular) Ionic Usually made form a metal and a nonmetal Composed of ions Electrons transferred between atoms Representative particle is called a formula unit Held together with ionic bonds Made from nonmetals Atoms in covalent bond are sharing electrons Representative particle is called a molecule Held together with covalent bonds

Characteristics of Ionic and Covalent Compounds Ionic  Solids at RT  High m.p. (usually above 300°C)  Can conduct an electric current in solution Covalent  Solids, liquids or gases at RT  Low m.p. (usually below 300°C)

What holds atoms together in a compound? Understand electrical nature of matter Like charges repel Unlike charges attract

Ionic Bonding Atoms lose or gain electrons to form ions Oppositely charged ions attract to form an ionic bond

Ionic Compounds Composed of  a cation (positive ion)  an anion (negative ion) Two types  binary ionic  ternary (complex) ionic

GroupLose or gain e-Charge when form an ion 1Lose 11+ 2Lose 22+ 3Lose 3 (Al)3+ 4 5Gain 3 (N, P)3- 6Gain 2 (O, S, Se)2- 7Gain Charges of ions of the representative elements

Names of Monoatomic Cations Metals  Lose electrons to form a positive ion (cation)  Group 1, 2 cations (predictable charge) Sodium lose 1 electron  sodium ion Na  Na 1+

Names of Monoatomic Anions Nonmetals  Gain electrons to form a negative ion (anion)  Names of nonmetal anions end in “ide” sulfur  sulfide ionS  S 2- nitrogen  nitride ionN  N 3- chlorine  chloride ionCl  Cl 1-

Writing Formula for Ionic Compounds Ions combine so that there is net charge of zero for the compound.  Total cation charge + total anion charge = 0 Write cation (positive ion) first Write anion (negative ion) second Change the number of each ion so that the charges add to zero

Binary Ionic Composed of two elements  a metal and a nonmetal Charge of cation + charge of anion = 0 Example: NaCl + = NaCl (charge =0) Na 1+ Cl 1-

Na 2 O

Mg 2+ and P 3- + = Mg 3 P = 0 Mg 2+ P 3-

Practice cationanionFormula K 1+ Br 1- Na 1+ I 1- Mg 2+ O 2- Fe 2+ Cl 1- Cu 1+ N 3- Cr 3+ S 2-

Practice cationanionFormula K 1+ Br 1- Na 1+ I 1- Mg 2+ O 2- Fe 2+ Cl 1- Cu 1+ N 3- Cr 3+ S 2- KBr NaI MgO FeCl 2 Cu 3 N Cr 2 S 3

Naming Binary Ionic Compounds of Cations with Fixed Charges Write cation name first  name of element Write anion name second  change ending of element’s name to “ide” Na 2 Ssodium sulfide BaCl 2 barium chloride MgOmagnesium oxide

Practice AlP MgSe BeBr 2 NaI SrCl 2 BaO LiF K 2 S Aluminum phosphide magnesium selenide berylium bromide sodium iodide strontium chloride barium oxide lithium fluoride potassium sulfide

Oxidation States of Transition Metals Most transition metals have more than one oxidation state (possible charge)  Cr: 2+, 3+, 6+  Mn: 2+, 3+, 4+, 6+, 7+  Ti: 2+, 3+, 4+  Pb: 2+, 4+

Names of Monoatomic Cations Transition metal cations (unpredictable charge) This includes metals under the staircase Iron lose 2 electrons  iron (II) ion Fe  Fe 2+ Iron  iron (III) ion Fe  Fe 3+ lead  lead (IV) ion Pb  Pb 4+ Transition metal names MUST include a roman numeral in the name to indicate the charge on the metal cation Exceptions: Ag +1, Zn +2, Cd +2

Naming Binary Compounds of Cations with Variable Charges Fe 3+ = cation Cl 1- = anion 1. Write name of cation- name of element 2. Indicate charge of cation by using a roman numeral in parentheses after name of cation 3. Write name of anion changing the ending to “ide” FeCl 3 Iron (III) chloride

FormulaCationAnionName Fe 3 P 2 SrO namecationanionformula Calcium chloride Aluminum sulfide Copper (I) nitride

FormulaCationAnionName Fe 3 P 2 Fe +2 P -3 Iron II phosphide SrOSr +2 O -2 Strontium oxide namecationanionformula Calcium chloride Ca +2 Cl -1 CaCl 2 Aluminum sulfide Al +3 S -2 Al 2 S 3 Copper (I) nitride Cu +1 N -3 Cu 3 N

Ternary Ionic Compounds Composed of more than two elements Composed of one or more polyatomic ions Polyatomic ions  Ions composed of two or more elements held together with covalent bonds  Charge of the ion is for the entire grouping of atoms  Each polyatomic ion has a unique name, formula and charge SO 4 -2 sulfate ion

Ternary Ionic Compounds Treat polyatomic ion as a single group;charge is for the whole group Write cation first Write anion second

Practice CationAnionFormula Na 1+ NO 3 1- NaNO 3 (1 sodium ion)(1+) + (1 nitrate ion)(1-) = 0 H 1+ CN 1- K 1+ ClO 3 1- Ba 2+ CO 3 2- Na 1+ OH 1- Mg 2+ SO 4 2- HCN KClO 3 BaCO 3 NaOH MgSO 4

Ba 2+ + OH 1-  (1 Ba ion)(+2) + (2 hydroxide ions)(-1)= 0  2+1- must put parentheses around polyatomic ion to indicate how many of those ions present in compound if there are more than one. Sn 2+ + NO 3 1- Sn(NO 3 ) 2 Ba(OH) 2

Mg 2+ and PO = Mg 3 (PO 4 ) = 0 Mg 2+ PO 4 3-

Naming Ternary Ionic Compounds with Cations of Fixed Charges Write name of cation first Write name of polyatomic ion Example  Na 2 SO 4 sodium sulfate  Ba(OH) 2 barium hydroxide

Practice Sr(NO 3 ) 2 HCN KClO 3 BaCO 3 Ca 3 (PO 4 ) 2 NH 4 Cl H 2 O 2 KMnO 4 strontium nitrate hydrogen cyanide potassium chlorate barium carbonate calcium phosphate ammonium chloride hydrogen peroxide potassium permanganate

Naming Ternary Compounds of Cations with Variable Charges 1. Write name of cation- name of element 2. Indicate charge of cation by using a roman numeral in parentheses after name of cation 3. Write name of polyatomic anion Fe 2 (SO 4 ) 3 Iron (III) sulfate Fe 3+ = cation SO 4 2- = anion

Practice Sn 3 (PO 4 ) 4 Ni(CN) 3 Fe(OH) 2 Hg(NO 3 ) 4 CuSO 4 PbCO 3 CoCrO 4 tin (IV) phosphate nickel (III) cyanide iron (II) hydroxide mercury (IV) nitrate copper (II) sulfate lead (II) carbonate cobalt (II) chromate

Covalent Compounds (molecular compounds) Nonmetals form covalent bonds by sharing electrons Representative particle is called a molecule There are no charged particles in a covalent compound

Naming Binary Covalent Compounds Use prefixes to indicate the number of atoms of each element in the compound mono 1 di 2 tri 3 tetra 4 penta 5 hexa6 hepta7 octa8 nona9 deca 10

Naming Binary Covalent Compounds Examples:  CS 2 carbon disulfide  CCl 4 carbon tetrachloride  N 2 O 5 dinitrogen pentoxide  COcabon monoxide Usually the first element in formula is element from the lower group number The prefix “mono” is used only with oxygen and only if oxygen is the second element

Write the formula  Sulfur hexafluoride  Dinitrogen trioxide  Tetraphosphorous trisulfide  Boron trichloride  Xenon tetrafluoride  Chlorine dioxide  Carbon tetraiodide SF 6 N 2 O 3 P 4 S 3 BCl 3 XeF 4 ClO 2 CI 4

Write the name As 4 O 6 SO 2 SbF 5 PCl 3 NO IF 5 H 2 O Tetraarsenic hexoxide sulfur dioxide antimony pentafluoride phosphorous trichloride nitrogen monoxide iodine pentafluoride dihydrogen monoxide

Diatomic elements Some elements exist in nature only as molecules  2 atoms of that element form a covalent bond  Br,I,N,Cl,H,O,F As elements these are written as follows: Br 2, I 2, N 2, Cl 2, H 2, O 2, and F 2  2H 2 + O 2  2H 2 O  4Fe + 3O 2  2Fe 2 O 3

Acids HClhydrochloric acid HNO 3 nitric acid H 2 SO 4 sulfuric acid H 2 CO 3 carbonic acid H 3 PO 4 phosphoric acid CH 3 COOHacetic acid