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Ions: Electron Configuration; Memorization; Ion Sizes; Chemical Bonding

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You must know the most stable ions an atom makes to be able to predict Ion ... Don't forget your Zeff, Rubidium has more protons, more Zeff. ... – PowerPoint PPT presentation

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Title: Ions: Electron Configuration; Memorization; Ion Sizes; Chemical Bonding


1
Ions Electron Configuration Memorization Ion
Sizes Chemical Bonding
2
Ions, Ions, Ions
  • You must know the most stable ions an atom makes
    to be able to predict Ion Electron configuration
    Ion size and how it will bond.
  • You are going to have to memorize the ion chart
    once and for all.
  • What ions are easy to remember? (hint P.T.)
  • Are there patterns for the rest? -1? -2? -3?
  • Dont the metals tell you in their names?

3
Ion Chart
  • POSITIVE IONS (cations) NEGATIVE IONS
    (anions)
  • Hydrogen H 1                                
    Bromide Br 1-
  • Lithium Li 1                                    
    Chloride Cl 1-
  • Sodium Na 1                                      
           Fluoride F 1-
  • Potassium K 1                                
    Iodide I 1-
  • Cesium Cs 1
  • Silver Ag 1
  • Copper ( I ) Cu 1                                
    Oxide O 2-
    cuprous)                             Sulfide
    S 2-
  • Mercury ( I ) Hg2 2
  • (also called mercurous)
  • Ammonium NH41                                
    Nitride N 3-
  • Barium Ba 2                                      
                  Phosphide P 3-
  • Magnesium Mg 2                                
    Acetate C2H3O2 1-
  • Calcium Ca 2                                     
        Cyanide CN 1-
  • Strontium Sr 2                                   
          Hydroxide OH 1-
  • Zinc Zn 2                                        
             Nitrite NO2 1-
  • Cadmium Cd 2                                     
            Nitrate NO31-
  • Copper ( II ) Cu 2                               
                          Chlorate ClO31-

Come directly from periodic table
Remember ate always has one more oxygen than
ite
So, if youre studying efficiently, youll
recognize that memorizing the -3 and -2 is easier
and assuming the rest are -1 can be effective
4
Ion Electronfiguration Ion Sizes
  • Most form bonds that allow the atoms that form
    them to achieve stable noble gas configurations
  • Ex Determine the charge and write the electron
    configuration for each of the atoms when it forms
    its most stable ion
  • Mg P Br Rb
  • Mg2 P3 Br - Rb1
  • Mg2 1s2 2s2 2p6 P3 1s2 2s2 2p6 3s2 3p6
  • Br - (Kr) Rb1 (Kr)
  • These last two are isoelectronic, they have the
    same electron configuration

5
But do they have the same size? Put them in order
from smallest to largest
  • Mg2 1s2 2s2 2p6 (Ne)
  • P3 1s2 2s2 2p6 3s2 3p6 (Ar)
  • Br - (Kr) Rb1 (Kr)
  • Mg2 P3 Rb1 Br
  • Dont forget your Zeff, Rubidium has more
    protons, more Zeff.

6
Naming and writing correct ionic formulas Ionic
compound forms because its energy is lower than
if its elements remained separated.
  • Synthesis Reactions are the type that two or more
    ions combine to form an ionic compound
  • A B ? AB
  • Write the equation for potassium bonding with
    chlorine

7
Solutions
  • K Cl- ? KCl
  • Try Sr and F
  • Al and Se
  • Ba and O
  • Sr2 F- ? SrF2
  • Al3 Se2- ? Al2Se3
  • Ba2 O2- ? Ba2O2 ? BaO
  • Can you do this backwards? What is that?

8
Decomposition
  • Write the net ionic equation for the following
    ionic compounds to decompose
  • Calcium Chloride
  • Potassium Fluoride
  • Sodium Sulfate
  • Lithium Chromate
  • Most times you will be given the words and not
    the equation, MEMORIZE.

9
Solutions
  • CaCl2 ? Ca2 2Cl-
  • KF ? K F-
  • Na2SO4? 2Na SO4-2
  • Li2CrO4? 2Li CrO42-
  • So whats so bad about that? How about if we need
    to calculate the bond energies?

10
Bond energy remember that it takes less energy
to form a bond than to break it
  • Many separate processes go into forming an ionic
    solid
  • Solid to gas energy of sublimation
  • Gas to ionized gas 1st ionization energy
  • Gaseous molecule to gaseous atom bond energy
  • Gaseous atom to gaseous ion electron affinity
  • Positive ion combines with negative ion to form
    an ionic solid lattice energy (energy released
    when an ionic solid is formed from its gaseous
    ions)

11
?Hf heat of formation the sum of the energy
changes (dont forget to multiply by coefficients)
  • Given the following data determine the ?Hf for
    LiBr
  • Ionization energy for Li 520 kJ/mol
  • Electron affinity for Br -324 kJ/mol
  • Energy of sublimation 161 kJ/mol
  • Lattice energy -787 kJ/mol
  • Bond energy for Br2 193 kJ/mol
  • Write the equation
  • Li (s) ½ Br2 (g) ? LiBr (s)
  • Remember, when you add, be careful to multiply
    the energies by their coefficients if this
    applies
  • 520 (-320) 161 (-787) ½ (193) -334.5 kJ
    ?Hf

12
Covalent Bond energies
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