Ch. 15 � Ionic Bonding & Ionic Compounds by 1s84ji5

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									Ch. 6 – Chemical Bonding

Electron Configuration in Ionic Bonding
Ionic Bonds

Bonding in Metals
             Chemical Bonding

    Chemical bonds form when two or more
    atoms lose gain or share electrons with one
    another
   How elements react to form chemical bonds is
    one of the properties of an element
   There are several factors that influence bond
    formation between elements
               Electronegativity

   Elements with high electronegativity form
    anions (non-metals)
   Elements with low electronegativity form
    cations (metals)
   The biggest factor in the type of bond formed
    is the difference in electronegativity values
    between the elements involved
   The greater the difference in electronegativity
    between the elements, the stronger the bond
    that holds them together
    Electronegativity and Bonding
   The type of bond is a function of the difference in
    electronegativity of the elements involved
   When the electronegativity difference is great,
    > 1.67, the electrons are transferred, forming ions
       The attraction of the cations of one element to the anions
        of the other element form an ionic bond.
   When the electronegativty difference is smaller
    <1.67, electrons are shared between the elements
       Sharing of electrons forms a covalent bond
Ionic Compounds
Electron Configuration

                         •the electrons in
                         the highest
                         occupied energy
                         level of an
                         element’s atoms
                         •determines the
                         chemical props of
                         an element
Noble gas configuration = ns2np6
Na (1s22s22p63s1)  Na+ (1s22s22p6) + e-

         ionization
Transition metals – the charges of the
cations may vary, exceptions to the octet
rule (Ag)
Ionic Bonds
The force of attraction between anions and cations to
form a neutral compound = ionic bond.


                               Li has 1 valence
                               e- and F has 7.
                               They combine in
                               1:1 ratio and
                               both ions have
                               stable octets.
Binary Ionic
Compounds
Properties of ionic compounds
•Crystalline solids at room
temp.
•Electrically neutral
•High melting points
•When melted in a solution
they conduct electricity b/c the
ions move freely when voltage
is applied
Coordination number – indicates the number of
ions of opposite charge that surround the ion in a
crystal
Naming metal ions
   Metal ions names stay the same as their
    element name EXCEPT if the metal has
    more than one oxidation number.

(Look on your Elements and Ions to Know
  handout to find multiple oxidation numbers)
                Latin Names
   Antimony    Sb   Stibium
   Copper      Cu   Cuprum
   Gold        Au   Aurum
   Iron        Fe   Ferrum
   Lead        Pb   Plumbum
   Mercury     Hg   Hydragyrum
   Potassium   K    Kalium
   Silver      Ag   Argentum
   Sodium      Na   Natrium
   Tin         Sn   Stannum
   Tungsten    W    Wolfram
  Naming metal ions
If there is more than one oxidation number write the
    name of the element followed by its oxidation
    number written in Roman numerals and placed in
    parenthesis or use the Latin Nomenclature
             Roman Numeral/ Latin Name
Ex. Fe+2          Iron (II)/Ferrous (-ous lower charge)
      Fe+3        Iron (III)/Ferric (-ic higher charge)
      Cu+1        Copper (I)/Cuprous
      Cu+2        Copper (II)/Cupric
Examples
   Mg2+   Magnesium ion
   Fe3+   Iron (III) ion or Ferric
   Al3+   Aluminum ion
   Fe2+   Iron (II) ion or Ferrous

   Tin (IV) or Stannic     Sn4+
   Copper (I) or Cuprous    Cu1+
   Silver                   Ag1+
    Naming nonmetal ions
   If the ion is composed of one element:
        name the element but change its
        ending to “ide”.

   If the ion is composed of two or more elements:
        name the polyatomic ion (either memorized or looked up
    on a polyatomic ion chart.)
Naming nonmetal monatomic ions
end in “-ide”
   Cl1-   Chloride ion
   S2-    Sulfide ion
   F1-    Fluoride ion
   O2-    Oxide ion

Notice how close the spellings are,
SPELLING COUNTS!!!!
              Polyatomic ions
   Formed when nonmetallic elements are
    covalently bonded together with an unequal
    amount of protons and electrons, giving it an
    overall positive or negative charge
   Form ternary ionic compounds (made up of
    three or more different elements).
   The –ate has one more Oxygen in its formula
    than the –ite.
Naming nonmetal polyatomic ions
most end in “-ate”, “-ite”
   Sulfate ion     SO42-
   Hydroxide ion   OH1-
   Sulfite ion     SO32-
   Nitrate ion     NO31-
   Acetate ion     C2H3O21-

Notice how close the spellings are,
SPELLING COUNTS!!!!
          Naming Ionic Compounds
•Binary Compounds – only 2 elements
   •Name the cation – always comes first
      •Transition metals can form more than one cation--
      Roman numerals or Latin names are used to
      identify the ion
   •Name the anion
      •Use the beginning of the anion followed by the
      suffix “ide”
             •NaCl = sodium chloride
             •Ternary compounds – more that 2 elements
             • Name the cation
             • Name the anion (usually a polyatomic
             ion)
Writing binary ionic formulas:
•Use oxidation #’s & their LCM (you will learn
the crisscross method)
•The compound needs same number of + and –
ions to make it neutral (balanced)
•Always put the + ion first
•Use subscripts to indicate the amount of each
element
•EX: Na = 1+, Cl = 1-; need one of each so
NaCl
Metallic Bonds
Bonding in Metals
             Metallic bonds
             a. building blocks metal
             cations
             b. nature of the bond metal
             cations are held together by
             the sea of delocalized
             valence electrons
             c. examples Zn (s), Au(s),
             alloys such as bronze or
             brass
Electron mobility in metals

•Accounts for high
conductivity
•Helps explain why
metals are ductile and
malleable                Body-centered
                             cubic
•Simplest crystalline
solids
          Characteristics of Metals
   The unique bond formation of metals give
    them their defining characteristics
       Luster – reflection of light
       Conductivity – easily conduct electricity
       Malleability – ability to be shaped
       Ductility – drawn into a wire without breaking
   The more electrons involved in a metallic
    bond, the harder the metal will be

								
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