Periods
Families(Groups)
--same # valence electrons
As a general rule, metals don’t like to form
bonds(compounds) with other metals(They will
with themselves). Metals(+ ions) would rather
form bonds with nonmetals(- ions)!!
Covalent Bonding
• Involves the sharing of electrons.
• Covalent bonds form between nonmetals and
nonmetals.
Lewis Dot Structures
(aka Electron Dot Diagrams)
• Lewis dot structures are a shorthand to
represent the valence electrons of an atom.
• The structures are written as the element
symbol surrounded by dots that represent the
valence electrons.
Lewis Dot Structures(cont.)
• Lewis structures can also be used to show covalent bonding
between atoms.
• The bonding electrons are placed between the atoms and can
be represented by a pair of dots or a dash (each dash
represents one pair of electrons, or one bond).
Show the Lewis Dot Structures for the
following compounds:
O2
F2
H2O
Covalent Bonds(cont.)
• Sometimes electrons are shared equally
among nonmetals in a covalent bond.
Sometimes they are not.
• It’s as if one element is pulling on the
electrons just a little bit harder than the other.
Covalent Bonds(cont.)
Polar Covalent Bonds
Non-Polar Covalent Bonds
• One element is pulling harder
on the electrons than the
other(s).
• Unequal sharing of electrons.
• This cause them to set up
“poles”.
• One element will become
slightly positive and the other
slightly negative.
• Both elements are pulling
just as hard on the
electrons.
• Equal sharing of electrons.
Solutions with Polar and Non-Polar
Compounds:
• As a general rule, “Likes dissolve Likes”
– Polar substances dissolve polar substances!
• Ex. H2O dissolves NaCl(all ionic compounds are polar)
– Non-Polar substances dissolve Non-polar
substances.
• CO2 will dissolve in ethanol(CH3CH2OH) because both
are non-polar.
– Polar substances will not dissolve in Non-Polar
substances!!!
• Water and Oil do not mix!!!
Which compound is least affected by temperature?
Which compound’s solubility decreases as temperature increases?
How many
grams of KNO3
will dissolve in
100 g of water
at 60o C?
110 g
At what
temperature will
approximately 95
g of NaNO3
dissolve in 100 g
of water?
30 oC
At what temperature
will the same amount
of KNO3 and NaNO3
dissolve in 100 g of
water?
~ 68 oC
Name the following compounds:
1. NaCl
Sodium Chloride
2. CaO
Calcium Oxide
3. KF
Potassium Fluoride
4. Na2CrO4
Sodium Chromate
5. Ca(ClO3)2
Calcium Chlorate
6. Al2(CO3)3
Aluminum Carbonate
Writing Chemical Formulas:
Lithium and Selenium
Li+1Se-2
Li2Se
Calcium and Chlorate
Ca+2ClO3-1
Ca(ClO3)2
Beryllium and Phosphorus
Be+2P-3
Be3P2
Gallium and Carbonate
Ga+3CO3-2
Ga2(CO3)3
Write the formulas for the following
compounds:
1. Calcium Phosphate
Ca+2PO4-3
Ca3(PO4)2
2. Aluminum Acetate
Al+3C2H3O2-1
Al(C2H3O2) 3
3. Francium Phosphide
Fr+1P-3
Fr3P
Determine the oxidation state of both elements
in the following examples:
•
CuF2
Cu+2F-1
•
Co2S3
Co+3S-2
•
Fe2O3
Fe+3O-2
Chemical Equations:
• Reactants “yield” Products
• Reactants
Products
• Must know the 4 types of chemical reactions:
1.
2.
3.
4.
Decomposition AB A + B
Synthesis
A + B AB
Single Replacement AB + C AC + B
Double Replacement AB + CD  AD + CB