How to Name and Write the Formula for Chemical Compounds - PowerPoint PPT Presentation

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How to Name and Write the Formula for Chemical Compounds

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lithium bromide. CaI2. calcium iodide. K2S. potassium sulfide. MgO. magnesium oxide ... nickel (II) bromide. SnI2. tin (II) iodide. PbS2. lead (IV) sulfide. FeO ... – PowerPoint PPT presentation

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Title: How to Name and Write the Formula for Chemical Compounds


1
  • How to Name and Write the Formula for Chemical
    Compounds

2
Types of Substances
  • Elements
  • Ionic Compounds
  • fixed charge cations
  • multiple-charge cations Stock and classical
    systems
  • polyatomic ions
  • Molecular Compounds
  • Acids

3
Recognizing Elements
  • chemical formula only has one capital letter
  • name only has one word

4
Elements Name from
Chemical Formula
  • match the given formula with one of those on the
    periodic table
  • name is given in the top half of the square for
    the element
  • e.g. Ca is calcium
  • Te is tellurium
  • Br2 is bromine

5
Elements Chemical
Formula from Name
  • chemical formula is taken directly from the
    periodic table
  • e.g. aluminum is Al, silicon is Si
  • memorize the Magnificent Seven, which start at
    element 7 N2, O2, F2, Cl2, Br2, I2, At2
  • also memorize H2, and the two exceptions P4 and S8

6
Recognizing Ionic Compounds
  • chemical formula has two or more capital letters
    the first symbol is for a metallic element
  • first word in its name is the name of a metallic
    element

7
Ionic Bonds
  • form when a cation (positively-charged metal ion)
    binds to a cation (negatively-charged nonmetal
    ion)
  • valence electrons are transferred from the metal
    ion to the nonmetal ion, forming an ionic bond

8
Types of Ionic Compounds
  • fixed charge cations the metal only has one
    charge
  • multiple-charge cations the metal can have more
    than one charge. Use either the Stock (preferred)
    or classical (out-of-date) system
  • polyatomic ions the metal ion is bound to a
    group of nonmetals that stick together

9
Ionic Compounds Name
from Chemical Formula
  • e.g. NaCl
  • name the metal ion first
  • in this example, the metal ion is sodium
  • name the nonmetal ion
  • in this example, the nonmetal ion is chloride
  • the correct name is sodium chloride

10
Other Examples
  • LiBr
  • lithium bromide
  • CaI2
  • calcium iodide
  • K2S
  • potassium sulfide
  • MgO
  • magnesium oxide

11
Ionic Compounds
Chemical Formula from Name
  • e.g. lithium iodide
  • write the metal ions symbol first
  • in this example, the metal ions symbol is Li1
  • write the nonmetal ions symbol next
  • in this example, the nonmetal ions symbol is I1-

12
  • write the symbols side-by-side
  • Li1 I1-
  • Cross Your Heart!
  • Li1I1
  • reduce to LCM do NOT write out 1
  • correct formula is
  • LiI

13
Other Examples
  • calcium chloride
  • CaCl2
  • cesium selenide
  • Cs2Se
  • strontium sulfide
  • SrS
  • aluminum oxide
  • Al2O3

14
Multiple Charge Cations
  • cation is the name given to the
    positively-charged metal ion
  • multiple charge cations are identified by a
    dotted line on periodic table
  • e.g. iron ion can be Fe3 (more common written
    on top of dotted line) or Fe2 (less common
    written below dotted line)

15
Ionic Compounds with Multiple Charge Cation Name
from Chemical Formula
  • e.g. FeCl3
  • name the metal ion first
  • in this example, the metal ion is iron
  • name the nonmetal ion
  • in this example, the nonmetal ion is chloride

16
Determining the Charge
  • metal charge is same as subscript on nonmetal ion
  • in this example, the charge is 3
  • write the charge as a Roman numeral in brackets
  • the correct name is iron (III) chloride

17
Other Examples
  • NiBr2
  • nickel (II) bromide
  • SnI2
  • tin (II) iodide
  • PbS2
  • lead (IV) sulfide
  • FeO
  • iron (II) oxide

18
Ionic Compounds with Multiple Charge Cation
Chemical Formula from Name
  • e.g. cobalt (II) fluoride
  • write the metal ions symbol first. Its charge is
    given by the Roman numeral in brackets.
  • in this example, the metal ions symbol is Co2
  • write the nonmetal ions symbol next
  • in this example, the nonmetal ions symbol is F1-

19
  • write the symbols side-by-side
  • Co2 F1-
  • Cross Your Heart!
  • Co1F2
  • reduce to LCM do NOT write out 1
  • correct formula is CoF2

20
Other Examples
  • copper (II) chloride
  • CuCl2
  • lead (IV) phosphide
  • Pb3P4
  • manganese (II) telluride
  • MnTe
  • cobalt (III) oxide
  • Co2O3

21
Classical System
  • be aware of it when you encounter it dont use
    it routinely!
  • root is Latin word for element e.g. leads root
    is plumb
  • -ous suffix is used to designate the cation of
    lesser charge
  • -ic suffix is used to designate the cation of
    greater charge

22
  • e.g. plumbic iodide refers to
  • lead (IV) iodide
  • e.g. cuprous chloride refers to
  • copper (I) chloride

23
More Practice
  • stannous fluoride
  • tin (II) fluoride
  • cupric sulfide
  • copper (II) sulfide
  • cobaltous hydride
  • cobalt (II) hydride
  • ferrous bromide
  • iron (II) bromide

24
Polyatomic Ions
  • name doesnt end in -ide
  • formula contains more than 2 capital letters
  • metal can be fixed or varible charge
  • nonmetal portion is a group of elements bonded
    together covalently
  • more than one anion in the group
  • listed in the Table of Polyatomic Ions
  • same rules for naming as ionic compounds

25
Naming Polyatomic Ions
  • e.g. KMnO4
  • name the metal ion first
  • in this example, the metal ion is potassium
  • name the polyatomic ion
  • in this example, the polyatomic ion is
    permanganate
  • the correct name is potassium permanganate

26
Examples Naming
Polyatomic Ions
  • NaNO3
  • sodium nitrate
  • CaCrO4
  • calcium chromate
  • Mg3(PO4)2
  • magnesium phosphate
  • CuSO4
  • copper (II) sulfate

27
Writing Formula for Polyatomic Ions
  • e.g. calcium borate
  • write the metal ions symbol first
  • in this example, the metal ions symbol is Ca2
  • write the polyatomic ions symbol next
  • in this example, the polyatomic ions symbol is
    BO33-

28
  • write the symbols side-by-side
  • Ca2 BO33-
  • Cross Your Heart!
  • Ca3(BO3)2
  • reduce to LCM do NOT write out 1
  • correct formula is
  • Ca3(BO3)2

29
Examples Writing Formulae for Polyatomic Ions
  • sodium hypochlorite
  • NaClO
  • potassium dichromate
  • K2Cr2O7
  • chromium (III) silicate
  • Cr2(SiO3)3
  • mercury (II) carbonate
  • HgCO3

30
Molecular Compounds
  • only contain nonmetals
  • any number of symbols
  • always use prefixes
  • must memorize the ones that dont follow the
    rules on p. xxx of text

31
Name From Formula
  • e.g. N2O4
  • name first nonmetal
  • in this example, nitrogen
  • name the second nonmetal
  • in this example, oxide

32
  • add prefixes to each, unless there is only one of
    the first nonmetal
  • in this example, the correct name is
  • dinitrogen tetraoxide

33
Examples
  • CO
  • carbon monoxide
  • CO2
  • carbon dioxide
  • NO3
  • nitrogen trioxide

34
Formula From Name
  • e.g. phosphorus pentachloride
  • write the symbol for the first nonmetal
  • in this example, P
  • write the symbol for the second nonmetal
  • in this example, Cl
  • the prefixes in the name indicate the number of
    each type of element in the molecule
  • in this example, PCl5

35
Examples
  • sulfur hexafluoride
  • SF6
  • phosphorus pentabromide
  • PBr5
  • dinitrogen tetraiodide
  • N2I4
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