Chapter 5-3
Warm - Up
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1. What is the difference between an ionic and
covalent bond?
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2. What type of bond is this:
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3. What is a polyatomic ion?
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4. What is the difference between ite and ate?
Chapter 5-3
The Structure of Matter
Compound Names and Formulas
Common Cations
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The name of the
cation is just like the
name of the element
Common Anions
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Anion are similar to
the element in them
but the ending is
changed
Combination of
elements
Determining the Charge of a
Transition Metal Cation
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How can you tell that the
iron ion in Fe2O3 has a
charge of 3+?
Oxide has a charge O23 x 2- = 6- charge
Total positive charge
must be 6+
Fe must be 3+
2 x 3+ = 6+
Writing Formulas for Ionic
Compounds
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What is the chemical formula for aluminum
fluoride?
1. Aluminum ion: Al3+
2. Fluoride ion: F3. Al3+F4. Least common multiple of 3 and 1 = 3
5. You need 3 positive and 3 negative charges.
6. AlF3
Practice
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Write the formulas for the following ionic
compounds (page 161):
1.
2.
3.
4.
lithium oxide
beryllium chloride
titanium (III) nitride
cobalt (III) oxide
Naming Covalent Compounds
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For 2 element
covalent compounds,
numerical prefixes tell
how many atoms of
each element are in
the molecule.
Boron trifluoride - BF3
Dinitrogen tetroxide –
N2O4
Empirical Formula

Empirical Formula –
composition of a
compound in terms of
the relative numbers
and kinds of atoms in
the simplest ratio.
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Used to determine
what things are made
of.
Emeralds are made of
beryl
Be3Al2Si6O18
Determining Empirical Formulas

If a 142 g sample of an unknown compound
contains only the elements phosphorus and
oxygen and is found to contain 62 g of P and 80
g of O. What is the empirical formula?
Phosphorus
Oxygen
62g P x 1 mol P
80 g O x 1 mol O
30.97 g P
16.00 g O
= 2.0 mol P
= 5.0 mol O
Empirical Formula = P2O5
Molecular Formula

Molecular Formula –
chemical formula that
shows the number
and kinds of atoms in
a molecule

Doesn’t show
arrangement