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I II III IV
Chemical Bonding
IonicBonding
Valence Electrons
Valence Electrons – outer energy level
electrons involved in bonding
12 63 4 75
8
Lewis Structures
Electron Dot Diagrams show valence e- as dots distribute dots like arrows
in an orbital diagram 4 sides = 1 s-orbital, 3 p-orbitals EX: oxygen
2s 2pO
X
Lewis Structures
Octet Rule Most atoms form bonds in order to obtain 8 valence
e-
Full energy level = stability ~ Noble Gases
Ne
Chemical Bonds
Why do chemical bonds form?
attractive force between atoms or ions binds them together as a unit
bonds form in order to…decrease potential energy (PE)increase stability
Properties of Ionic Compounds
Bond Formation Electrons are transferred from metal to nonmetal
Type of Structure Crystal Lattice
Physical State Solid
Melting Point High
Solubility in Water Yes
Electrical Conductivity Yes
Lewis Structures
Ionic Bonding – Electrons are transferred
from the metal atom to the nonmetal atom.
Lewis Structures
Ionic – the arrow shows the transfer of e-
Vocabulary
CHEMICAL FORMULA
FormulaUnit
IONIC
NaClNaCl
Vocabulary
COMPOUND
TernaryCompound
BinaryCompound
2 elementsmore than 2
elements
NaNONaNO33NaClNaCl
Vocabulary
ION
PolyatomicIon
MonatomicIon
1 atom 2 or more atoms
NONO33--NaNa++
1+
2+ 3+ 4+/4- 3- 2- 1-
0
Common Ion Charges
Also called Oxidation Numbers
Common Ion Charges
What do the common ion charges tell you?
The number of electrons that are either lost/gained or transferred in order to form an ionic bond.
For example: Na has a charge of +1, this means that Na will lose or transfer one electron to the non-metal ion when bonding.
When bonding, will the following atoms lose
or gain electrons? How many?
Potassium OxygenFluorineCalcium
Lose 1
Gain 2
Gain 1
Lose 2
Ionic Nomenclature
Writing Ionic Formulas
Write the cation first then the anion. Don’t show charges in the final formula.
Overall charge must equal zero. If charges cancel, just write symbols. If not, use subscripts to balance charges.
potassium chloride
magnesium oxide
Calcium fluoride
K+ Cl
Mg2+ O2
Ca2+ Fl
KCl
MgO
CaFl2
Ionic Nomenclature
Ionic Nomenclature
Writing Names of Ionic Compounds
Write the names of the cation first.
Change ending of the anion to -ide.
NaBr
K2S
CaI2
sodium bromide
Potassium sulfide
Calcium iodide
Ionic Nomenclature
Ionic Nomenclature
More on writing Names of Ionic Compounds
Polyatomic ions have special names.
Stock System - Use Roman numerals to show the ion’s charge for transition metals. Overall charge must equal zero.
NaNO3
K2SO4
NH4NO3
sodium nitrate
Potassium sulfate
Ammonium nitrate
Ionic Nomenclature
Fe2S
CuSO4
CoCl2
Iron(I)sulfide
Copper(II)sulfate
Cobalt(II)chloride
Ionic Nomenclature