Chemistry - Manistique Area Schools

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Chemistry
Chapter 8
Notes #2
Ionic Bonding/terms
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Anions and cations are held together by opposite
charges.
Many ionic compounds are referred to as salts or
oxides.
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Simplest ratio of elements in an ionic compound is
called the formula unit.
The bond is formed through the transfer of
electrons.
Electrons are transferred to achieve noble gas
configuration.
Ionic Bonding
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Cation + Anion
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The cation is always written first
Formula Units (instead of molecules)
The ions come together to neutralize the
charge (always have an overall charge of
zero)
Structure: Positive ions are surrounded by
negatives and vice versa
Ionic Bonding
Na Cl
The metal (sodium) tends to lose its one
electron from the outer level.
The nonmetal (chlorine) needs to gain one
more to fill its outer level, and will accept the
one electron that sodium is going to lose.
Ionic Bonding
+
Na
Cl
-
Note: Remember that NO DOTS
are now shown for the cation!
Ionic Bonding
Lets do an example by combining
calcium and phosphorus:
Ca

P
All the electrons must be accounted for, and
each atom will have a noble gas
configuration (which is stable).
Ionic Bonding
Ca
P
Ionic Bonding
2+
Ca
P
Ionic Bonding
2+
Ca
Ca
P
Ionic Bonding
2+
Ca
P
Ca
P
3-
Ionic Bonding
2+
Ca
Ca
P
3-
Ionic Bonding
2+
Ca
P
2+
Ca
P
3-
Ionic Bonding
Ca
2+
Ca
P
2+
Ca
P
3-
Ionic Bonding
Ca
2+
Ca
P
2+
Ca
P
3-
Ionic Bonding
2+
Ca
2+
Ca
2+
Ca
P
P
33-
Ionic Bonding
= Ca3P2
Formula Unit
This is a chemical formula, which
shows the kinds and numbers of atoms in
the smallest representative particle of the
substance.
For an ionic compound, the smallest
representative particle is called a:
Formula Unit
Naming Compounds
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Name Cation first, anion second
Monatomic cation – name of element
Monatomic anions – drop ending, add –ide
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Ex. Oxygen = oxide
Polyatomic ions = name of polyatomic
Transition metals – the oxidation number is
written as a roman numeral
Examples
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Sodium Chloride
Magnesium Fluoride
Potassium Nitride
Iron (III) oxide
Ammonium Sulfide
Lithium Carbonate
Strontium Phosphate
FeO
Fe2O3
Ionic Properties
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Ionic crystal = crystal lattice
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High melting points
High boiling points
Hard, rigid, and brittle
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3-dimensional geometric pattern of particles
Due to the high strength of the bonds
Energy to separate ions (1 mole) = lattice
energy

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