1. Ch. 6 Bonding
6.3 Ionic Bonding

2. Ionic Compounds ionic bonds do NOT form molecules
chemical formulas for ionic compounds represent the simplest ratio of ion types
made of anions and cations

3. Ionic Compounds
combined so that amount of positive and negative charge is equal
usually crystalline solid
formula of ionic compound depends on the charges of the ions combined

4. Formation attractive forces: repulsive forces: oppositely charged ions
nuclei and electron clouds of adjacent ions
repulsive forces:
like-charged ions
electrons of adjacent ions

5. Formation
distance between the ions creates a balance between those forces
ions minimize their PE by combining in an orderly arrangement called a crystal lattice

6. Formation specific lattice pattern created depends on: charges of ions
size of ions
Calcium Bromide:
each Ca2+ is surrounded by 8 F-
each F- is surrounded by 4 Ca2+
Sodium Chloride
each Na+ is surrounded by 6 Cl-
each Cl- is surrounded by 6 Na+

7. Lattice Energy
energy released when separate gaseous ion bond to form ionic solid
the larger the amount of energy released, the stronger the bond
since it is released, the value is negative
NaCl
-787.5
NaBr
-751.4
CaF2
CaO
-3385
LiCl
-861.3
MgO
-3760
KCl
-715

8. Ionic vs. Molecular ionic bonds and molecular bonds are both strong
ionic bonds connect all ions together
molecules are more easily pulled apart because intermolecular forces are weak

9. Ionic vs. Molecular Molecular Compounds:
low melting and boiling points
many are gases at room temperature
Because the intermolecular forces of the molecules are weak so they are easily separated

10. Ionic vs. Molecular Ionic Compounds: higher melting and boiling points
all are solid at room temperature
hard: Because of the strong forces, it is difficult for one layer of ions to move past another
brittle: if one layer is moved, the layers come apart completely

11. Ionic vs. Molecular Ionic Compounds: good conductors in liquid state
Because ions are free to move and carry charge
poor conductor in solid state
Because ions are fixed in place

12. Polyatomic Ions
charged group of covalently bonded atoms
Example: CN-

13. NH4+ : ammonium ion

14. O O S O O O H SO42- : sulfate ion OH- : hydroxide ion 5 x 6 = 30
total = = 32
OH- : hydroxide ion
= 8 total O S O O O H