Naming Compounds Writing Formulas

 There are more than 50 million named chemical substances  Many have common names that we use everyday like sugar, table salt, borax, and sand  They all have systematic names that make keep track of them easier and uniquely identify each one.

 Follow the Law of Definite Proportion.  Have a constant composition.  Same formula (atoms) every time  Two Major Types of Compounds  Ionic  Covalent or Molecular

 Covalent Compounds  Made of molecules  Made by joining nonmetal atoms together into molecules  Non-Metal Non-Metal Combinations  Soft solids, liquids, and gases  Carbon dioxide CO 2  Dihydrogen monoxide H 2 O

 Made of cations and anions  Positive ion bonded to negative ion  Metal Non-Metal Combinations  The electrons lost by the cation are gained by the anion  The cations and anions surround each other  Smallest ratio of ions in an ionic compound is a FORMULA UNIT.  All hard, brittle solids  Calcium chloride CaCl 2

K +1 Ca +2 Has lost two electrons  Positive ions  Formed by losing electrons  More protons than electrons  Metals usually Has lost one electron

 A negative ion  Has gained electrons  Non metals  Charge is written as a superscript on the right. F -1 Has gained one electron O -2 Has gained two electrons

 Shows the kind and number of atoms in the smallest piece/ratio of a substance  CO 2  C 6 H 12 O 6  AlBr 3

 The smallest whole number ratio of atoms in an ionic compound.  Ions surround each other so you can’t say which is hooked to which

 The Stock (Roman numeral) System used for Ionic Compounds  The Numerical Prefix System used for Covalent Compounds

 Write the name of the less electronegative element or polyatomic ion  Write down the name of the other element or polyatomic ion  Put a Roman numeral in parentheses after the first element name  The Roman numeral is equal to the oxidation state (charge) of the first element

 Composed of 2 different elements  Write down the name of the less electronegative element (metal)  Write down the root of the other element then add ---ide to the end.  Place the roman numeral in parentheses after the first element if needed  Roman # equals the charge of the first element

 For Elements in Groups 1, 2,13-18 on the Periodic Table you can tell what kind of ion they will form from their location on the table  Elements in the same group have similar properties  Including the charge when they are ions

 We have to figure those out some other way.  More on this later.

 We will use the systematic way  Cation- if the charge is always the same just write the name of the metal (Gr. 1, 2, 13)  Transition metals can have more than one type of charge  Indicate the charge with a Roman numeral in parentheses  How we determine this in a bit

 Na +1  Ca +2  Al +3  Fe +3  Fe +2  Pb +2  Li +1

 Potassium ion  Magnesium ion  Copper (II) ion  Chromium (VI) ion  Barium ion  Mercury (II) ion

 Anions are always the same when it comes to charge  Change the element ending to – ide  F -1 fluoride  S -2 sulfide  P -3 phosphide  Te -2 telluride 

 Cl -1  N -3  Br -1  O -2  Ga +3

 Sulfide ion  iodide ion  phosphide ion  Strontium ion

 Groups of atoms that stay together and have a charge  You must memorize these or use an ion sheet  Acetate C 2 H 3 O 2 -1  Nitrate NO 3 -1  Nitrite NO 2 -1  Hydroxide OH -1  Permanganate MnO 4 -1  Cyanide CN -1

 Sulfate SO 4 -2  Sulfite SO 3 -2  Carbonate CO 3 -2  Chromate CrO 4 -2  Dichromate Cr 2 O 7 -2  Phosphate PO 4 -3  Phosphite PO 3 -3  Ammonium NH 4 +1

EndingFormulaName (from the element that is not oxygen) ChlorineFormula ---ideNo oxygenS-2SulfideChlorideCl iteSome oxygen SO3-2SulfiteChloriteClO ateMore oxygen SO4-2SulfateChlorateClO 3 -1 Hypo ite Less oxygen HypochloriteClO -1 Per icMost oxygen PerchlorateClO 4 -1

 Binary Compounds  2 elements  Metal nonmetal  a cation and an anion  + -  To write the names just name the two ions.

 Easy with Representative elements  Groups 1, 2, 13  Charge determined by location in table  NaCl = Na + Cl - = sodium chloride  MgBr 2 = Mg +2 Br - = magnesium bromide

 The problem comes with the transition metals and in other variable charged cations  Elements not are not in groups 1, 2, or 13. Need to figure out their charges.  How?

 The compound must be neutral  Same number of + and – charges  Look up the charge on the negative  Calculate the total negative charge  Must be equal to total positive charge  Divide positive total by number of atoms  Result is equal to charge on positive  This is the Roman numeral

 Write the name of CuO  Copper is not in gr 1, 2, or 13 so need a roman numeral  O is -2 therefore  Copper must be +2 so the roman numeral = 2  Name is Copper (II) chloride

 Name the following: CoCl 3

 Write the name of Cu 2 S

 Fe 2 O 3

 Write the names of the following  KCl  Na 3 N  CrN  Sc 3 P 2  PbO  PbO 2  Na 2 Se

 Will have at least one polyatomic ions  At least three elements  Name the ions: Use a roman numeral if needed.  NaNO 3  CaSO 4  CuSO 3  (NH 4 ) 2 O

 LiCN  Fe(OH) 3  (NH 4 ) 2 CO 3  NiPO 4

 Things to remember:  The charges in a compound have to add up to zero 1. Write down each ion with charges 2. Make the charges equal by adding subscripts 3. Put polyatomic ions in parentheses before using a subscript

 Write the formula for calcium chloride.  Calcium is Ca +2  Chloride is Cl -1  Charge on compound must be 0.  So 2 Cl -1 are needed to make the charge = to zero.  CaCl 2  2 atoms of chlorine for every one atom of calcium

 Aluminum nitrate

 Lithium sulfide  tin (II) oxide  tin (IV) oxide  Magnesium fluoride  Copper (II) sulfate  Iron (III) phosphide

 gallium nitrate  Iron (III) sulfide  Ammonium chloride  ammonium sulfide  barium nitrate

 If cation has a (Roman Numeral), the number is the charge of the positive ion  If anions end in -ide they are probably off the periodic table (monoatomic) but can be cyanide, hydroxide  If anion ends in -ate or -ite it is polyatomic

Writing names and Formulas

 Nonmetal Nonmetal combinations  smallest piece is a molecule  Also called covalent compounds  not held together because of opposite charges

 Molecular compounds name tells you the number of atoms  Uses prefixes to tell you the number

 1 mono-  2 di-  3 tri-  4 tetra-  5 penta-  6 hexa-  7 hepta-  8 octa-

 9 nona-  10 deca-

 9 nona-  10 deca-  To write the name write two words PrefixnamePrefixname-ide

 9 nona-  10 deca-  To write the name write two words  One exception is we don’t write mono- if there is only one of the first element. PrefixnamePrefixname-ide

 9 nona-  10 deca-  To write the name write two words  One exception is we don’t write mono- if there is only one of the first element.  No double vowels when writing names (oa oo) except with i PrefixnamePrefixname-ide

 N 2 O  NO 2  Cl 2 O 7  CBr 4  CO 2  BaCl 2

 diphosphorus pentoxide  tetraiodide nonoxide  sulfur hexaflouride  nitrogen trioxide  carbon tetrahydride  phosphorus trifluoride  aluminum chloride

Writing names and Formulas

 Compounds that give off hydrogen ions when dissolved in water.  Must have H in them  will always be some H next to an anion  HCl  H 2 SO 4  The anion determines the name

AnionExampleAcidExample ….ideCl - 1 chloride Hydro…icHCl Hydrochloric acid …..iteClO2 - 1 chlorite ….ousHClO 2 Chlorous acid Hypo…..iteClO -1 hypochlorite Hypo….ousHClO Hypochlorous acid …..ateClO chlorate ….icHClO 3 Chloric acid Per…ateClO perchlorate Per……icHClO 4 Perchloric acid

 Rule 1: If the anion attached to hydrogen is ends in -ide, put the prefix hydro- and change -ide to -ic acid  Example: HCl - hydrogen ion and chloride ion  Example: H 2 S hydrogen ion and sulfide ion

 If the anion has oxygen in it  it ends in -ate of -ite  Rule 2: change the suffix -ate to -ic acid  Example: HNO 3  Hydrogen and nitrate ions  Rule 3: change the suffix -ite to -ous acid  Example: HNO 2 Hydrogen and nitrite ions

 HF  H 3 P  H 2 SO 4  H 2 SO 3  HCN  H 2 CrO 4

 Hydrogen will always be first  name will tell you the anion  make the charges cancel out.  Rule 1: hydro- no oxygen, -ide ion  Rule 2 : no hydro, -ate comes from -ic,  Rule 3: no hydro -ite comes from -ous

 hydroiodic acid  acetic acid  carbonic acid  phosphorous acid  hydrobromic acid

 A solid compound with a specific number of water molecules bonded to it  Release water when heated at fairly low temperatures  Anhydrous SolidxH2O)  Common Example: CuSO 4 5H 2 O  Copper (II) sulfate pentahydrate  The penta indicates five water molecules for each copper (II) sulphate particle

 The prefix indicates the number of water molecules bonded to the anhydrous salt

 zinc sulphate heptahydrate  copper (I) sulphite monohydrate  cobalt (II) fluoride tetrahydrate  lithium nitrate trihydrate  sodium sulphate decahydrate  calcium nitrate trihydrate

 Na2SO4 10H2O  LiNO3 3H20  Cu2SO3 3H20  Ca(N03) 2 2H20  MgS04 7H20  ZnS04 7 H20