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					SCH3U                 Nomenclature: Formulae and Names
Terms:

VALENCE:
 The valence of an element is defined as the number of atoms of hydrogen (+1) or of chlorine (-1) with
which ONE atom of the element combines. Most valence numbers can be determined from Family
number. Some elements have more than one valence number (multi valence ions). The term “valence” is
similar to the idea of “combining capacity” since it indicates the number of bonds which will be formed.

RADICALS:
A radical is a group of atoms which remains intact through many chemical reactions.
e.g.    a sulfate RADICAL, SO4-2 ( valence = 2) vs.         a sulfide ION, S-2 (valence = 2)

Note: Radicals as well as elements have a valence.

                                       BINARY COMPOUNDS

Binary Compounds are compounds composed of two different elements.
There are 5 different types of binary compounds:
                       1. Monovalent metal – Nonmetal     e.g. NaCl sodium chloride
                       2. Two nonmetals                  e.g. CO2 carbon dioxide
                       3. Compounds of hydrogen (+1 valence) NOT dissolved in water
                                                         e.g. HBr hydrogen bromide
                       4. Binary Acids [ Compounds of hydrogen dissolved in water (aq) ]
                                                         e.g. HCl(aq) hydrochloric acid
                       5. Multivalent metal – Nonmetal   e.g. FeCl3 iron (III) chloride or ferric chloride

1. Monovalent Metal – Nonmetal [Simple Ionic Compound]
       To name, state the name of the metal element first, the nonmetal element second and change the
ending of the nonmetal element to “ide”. No prefixes are used.
       Use the crossover rule to determine the formula, using the valence or ionic charge of each ion.
The resulting compound should be neutral (net charge = zero)

Sodium bromide               __________              KI            __________________________
Sodium fluoride              __________              KCl           __________________________
Sodium oxide                 __________              K2S           __________________________
Sodium phosphide             __________              K3N           __________________________
Calcium iodide               __________              MgBr2         __________________________
Calcium chloride             __________              MgF2          __________________________
Calcium oxide                __________              MgO           __________________________
Calcium sulphide             __________              Mg3P2         __________________________
Aluminum fluoride            __________              AlP           ___________________________
Aluminum oxide               __________              Al2S3         ___________________________
2. Nonmetal – Nonmetal           [Covalent binary compounds]
Write the LEAST ELECTRONEGATIVE element first in the name and in the formula.              E.g. CCl4
   Naming Method #1: Prefix system ( also called Classical) carbon tetrachloride
1=mono       2=di             3=tri      4=tetra     5=penta        6= hexa                7= hepta
If there is just one of the first element in the compound, do not use “mono” prefix. If more than one, use
the correct prefix. For the second element, use the prefix + root element name + “ide” ending

   Naming Method #2: Stock system using Roman Numeral to indicate valence of first element. Refer to
text’s periodic table for possible valences of nonmetals.
                                               carbon (IV) chloride

nitrogen dioxide       _____________         CBr4    ______________________________________
boron trifluoride      _____________         SO2     ______________________________________
carbon tetrafluoride   _____________         SiS2    ______________________________________
neon hexafluoride      _____________         P2O5    ______________________________________
diarsenic trisulphide ______________         NO3     _________________________________________
carbon monoxide        ______________        CS2     _______________________________________
silicon dioxide        ______________        BrCl3 _______________________________________
dinitrogen tetraoxide _______________        C3N4 _______________________________________
phosphorus pentabromide ___________          XeF5 _______________________________________
sulphur trioxide       _______________       P2S3    ________________________________________


3. Compounds of Hydrogen (valence +1) not dissolved in water.
To name: Do not use the mono, di, tri system. Write hydrogen then the root of the other element adding
the ending “ide”.
To determine formula, use valence from periodic table, giving H a valence of +1 and crossover to obtain
a neutral compound.

Hydrogen bromide              _________              HF             ____________________________
Hydrogen sulphide             _________              H2Te           ____________________________
Hydrogen phosphide            _________              H3N            ____________________________
Hydrogen iodide               _________              HCl            ____________________________
Hydrogen chloride             _________              H2S            ____________________________
Hydrogen selenide             _________              H3As           ____________________________
4. Binary Acids [ compounds of hydrogen (valence +1) dissolved in water (aq) ]
   To name, write the prefix “hydro”, the root of the second element and add the suffix “ic”, then the
word “acid”.
   Write the formula using valence of +1 for H, normal valence for the second element. Add (aq) after the
formula to show it is dissolved in water.

Hydrobromic acid              _____________          HF (aq)        __________________________
Hydrosulphuric acid           _____________          H3N (aq)       __________________________
Hydroiodic acid               _____________          HCl (aq)       __________________________
Hydroselenic acid             _____________          H2S (aq)       __________________________


5. Multi-valent Metals – Non metal compounds
Stock or Roman Numeral Naming Method: Use a Roman Numeral to indicate the valence (charge) of the
positively charged metal ion, followed by the root of the nonmetal and the “ide” ending.

Classical Method of Naming: Use the root of the metal, adding the suffix “ous” for the lower valence
(charge) or the suffix “ic” for the higher valence (charge) of the positively charged metal ion, followed by
the root of the nonmetal and the “ide” ending.

Roman Numeral and Classical names of Different Ions of Some Common Multi-Valent Metal Ions:
  Metal         Ion of      Stock Name      Classical        Ion of  Stock Name        Classical
               Lower                          Name          Higher                      Name
               Charge                                       Charge
   Iron          Fe2+         iron (II)       ferrous         Fe3+      iron (III)       ferric
                    1+                                           2+
  Copper         Cu          copper (I)      cuprous          Cu      copper (II)       cupric
    Tin          Sn2+          tin (II)      stannous         Sn4+       tin (IV)       stannic
   Lead          Pb2+         lead (II)     plumbous          Pb4+      lead (IV)      plumbic

Use ionic charges (valence) and crossover to determine formulas of these compounds.
                                                          Stock                  Classical
Copper (I) chloride___________ CuO          _________________________________________________

Copper (II) chloride___________ CuI2         _________________________________________________

Lead (II) oxide     ___________     PbS      _________________________________________________

Lead (IV) oxide     ___________     Pb3P4    _________________________________________________

Iron (II) sulphide ___________       FeO     _________________________________________________

Iron (III) oxide    ___________      Fe2O3 _________________________________________________

Tin (II) iodide     ___________      SnO2    _________________________________________________

Tin (IV) sulphide ___________        SnS     ________________________________________________
                      TERNARY COMPOUNDS (contain 3 or more elements)
1. Monovalent Metal + Radical
                              Common Radicals which you must memorize:
              +1                       -1                          -2                            -3
      +1                       -1                            -2                         -3
NH4        (ammonium)       OH ( hydroxide)             CO3 (carbonate)            PO4       (phosphate)
                            NO3-1 (nitrate)             SO4-2 (sulphate)           PO3-3     (phosphite)
                            NO2-1 (nitrite)             SO3-2 (sulphite)           PO2-3     (hypophosphite)
                            ClO4-1 (perchlorate)
                            ClO3-1 (chlorate)
                            ClO2-1 (chlorite)
                            HCO3-1 (hydrogen
                            carbonate) (bicarbonate)
                            C2H3O2-1 (acetate)

Sodium chlorate               ____________             KNO3        ___________________________
Sodium hydroxide              ____________             KC2H3O2     ___________________________
Sodium nitrate                ____________             KOH         ___________________________
Sodium sulphate               ____________             KClO3       ___________________________
Sodium carbonate              ____________             K2CO3       ___________________________
Sodium phosphate              ____________             K3PO4       ___________________________
Calcium bicarbonate           ____________             Rb3PO4      ___________________________
Calcium carbonate             ____________             LiNO3       ___________________________
Zinc sulphate                 ____________             BeCO3       ___________________________
Magnesium acetate             ____________             AgNO3       ___________________________
Aluminum phosphate            ____________             Cd(C2H3O2)2 ___________________________
Aluminum sulphate             ____________             BaSO3       ___________________________
Aluminum nitrate              ____________             Al(OH)3     _________________________________________

Magnesium sulphite            ____________             NH4OH       ____________________________


2. Multi valent Metals + Radical (use Roman Numeral to indicate charge on metal)

copper (I) chlorate           ____________             Sn(NO3)2    ____________________________
copper (II) nitrate           ____________             Sn(NO3)4    ____________________________
gold (I) nitrite              ____________             WPO4        ____________________________
mercury (II) phosphite        ____________             CuSO2       ____________________________
mercury (I) hydroxide         ____________             CuSO4       ____________________________
iron (II) perchlorate         ____________             Cu2SO3      ____________________________
3. Multi valent Metals and a Radical – THE OLD SYSTEM
The use of “ic” for higher valence and “ous” for lower valence as used for binary
compounds also can be used to name ternary compounds. Do not use this method (unless
specifically requested) to name a compound from a formula. The STOCK method of
Roman Numerals is preferred. However, you do need to be able to translate an old system
name into a proper modern name or to write a formula from the old name.

Give the Modern Name (STOCK / Roman Numeral) and the correct chemical formula for
each of the following old system names:

Old System Name              Formula                Stock System Name
Mercurous sulphite           _________              __________________________________
Auric hypophosphite          _________              __________________________________
Cobaltous nitrate            _________              __________________________________
Cupric nitrite               _________              __________________________________
Cuprous hydroxide            _________              __________________________________
Plumbous hyponitrite         _________              __________________________________


4. Radicals containing Oxygen – Parents and their Daughter Radicals

Some of the radicals which contain oxygen, e.g. ClO3, NO3, SO4, PO4, are able to lose one or two of
their oxygen atoms, or gain one extra oxygen atom without changing the valence (i.e. charge) of the
radical. As the formula of the radicals change, so do their names, according to the following rules.
Note that there is a ROOT name which is followed by a suffix and which may also have a prefix.

Number of Oxygen Atoms Formula Examples                      Name                    Name Examples
Parent Radical plus 1 O  ClO4-1                       per + ROOT + ate           perchlorate
                         SO5-2                                                   persulphate
                         PO5-3                                                   perphosphate
Parent Radical           ClO3-1                              ROOT + ate          chlorate
                         SO4-2                                                   sulphate
                         PO4-3                                                   phosphate
Parent Radical minus 1 O ClO2-1                              ROOT +       ite    chlorite
                         SO3-2                                                   sulphite
                         PO3-3                                                   phosphite
Parent Radical minus 2 O ClO-1                        Hypo + ROOT + ite          hypochlorite
                         SO2-2                                                   hyposulphite
                         PO2-3                                                   hypophosphite

NOTE: daughter radicals all have the same valence (i.e. charge) as the parent radical
Practice using parent and daughter radicals in the following exercise:

Potassium chlorate            ___________            CaSO4 _________________________________
Potassium perchlorate         ___________            CaSO3 _________________________________
Potassium chlorite            ___________            CaSO2 _________________________________
Potassium hypochlorite        ___________            AlPO2 _________________________________
Magnesium sulphate            ___________            AlPO3 _________________________________
Magnesium sulphite            ___________            AlPO4 _________________________________
Magnesium hyposulphite        ___________            H3PO2 _________________________________
Aluminum phosphate            ___________            Ba3(PO4)2 _______________________________
Aluminum phosphite            ___________            Ag2SO2 ________________________________
Aluminum hypophosphite        ___________
Calcium phosphite             ___________
Beryllium hyposulphite        ___________
Barium hypophosphite          ___________
Another way of organizing and learning some of the common radicals that contain oxygen:
Charge        Per ------- ate              ------ate           -------ite          Hypo -------- ite
  on            [add 1 O]            [parent radical]       [remove 1 O]           [remove 2 O’s]
Radical
  -1      ClO4-1 perchlorate ClO3-1                    ClO2-1                   ClO1-1
                                 chlorate              chlorite                 hypochlorite
                                       -1                   -1
  -1                             NO3                   NO2
                                 nitrate               nitrite
                                      -2
  -2                             SO4                   SO32-                    SO22-
                                 sulphate              sulphite                 hyposulphite
                                      -2
  -2                             CO3
                                 carbonate
  -3                             PO4-3                 PO3-3                    PO2-3
                                 phosphate             phosphite                hypophosphite
And the oxyacids that they form:
# of H+    Per ------- ic acids         ------ic acids     -------ous acids      Hypo -------ous acids

   1       HClO4(aq)               HClO3(aq) chloric    HClO2(aq) chlorous       HClO(aq)
           perchloric acid         acid                 acid                     hypochlorous acid
   1                               HNO3(aq) nitric acid HNO2(aq) nitrous
                                                        acid
   2                               H2SO4(aq) sulphuric H2SO3(aq) sulphurous      H2SO2(aq)
                                   acid                 acid                     hyposulphurous acid
   2                               H2CO3(aq) carbonic
                                   acid
   3                               H3PO4(aq) phosphoric H3PO3(aq)                H3PO2(aq)
                                   acid                 phosphorous acid         hypophosphorous
                                                                                 acid

				
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