Tuesday, January 22, 2008
• Final Grades
• Quick Review
• Electron configurations
• Types of bonding
• Ions and Ionic Compounds
• Lewis Structures
•Homework for Tuesday
Page 436, #18, 20a,d,e, 21-22, 23a,b,
24-27, 28a,b,c, 29
Homework for Wednesday
Page 436, #30-38
Lewis Structures Activity WS
QUIZ FRIDAY
Electron Configurations
Give the electron configurations for the
following elements:
Sodium
Sulfur
Carbon
What about for these ions?
Sodium ion (Na+)
Aluminum ion (Al3+)
Types of Bonding
Ionic Bonding - The attraction between ___________________
Between __________ and ________
Involves ____________ of electrons
Covalent Bonding - A type of bonding in which atoms
____________ electrons
Between two ______________
Involves _________ of electrons equally
Polar Covalent Bonding - A ___________ bond in which the
electrons are ______ shared
equally because one atom attracts
the shared electrons _________
than the other atom
Ions & Ionic Compounds
Charges on Ions
Group IA metals always form _________________
Group IIA metals always form ________________
Aluminum in Group IIIA always forms _________
Group VI nonmetals always form ______________
Group VII nonmetals always form _____________
Characteristics of Ionic
Compounds
High Melting Point
Conduct electricity (when dissolved in water)
Valence Electrons
What are valence electrons?
The electrons in the ____________
principal energy level.
How many valence electrons do each of the
following atoms have?
sodium?
chlorine?
oxygen?
Lewis Structures
Lewis Structures – A representation of a molecule
or polyatomic ion showing how valence electrons
are arranged among the atoms in the molecule or
ion
In a Lewis dot structure for an element, the
valence electrons are written as dots
surrounding the symbol for the element.
Place one dot on each side first, and when all
four positions are filled, the remaining dots
are paired with one of the first set of dots.
A maximum of two dots are placed on each
side.
Lewis Structures
For nonmetals especially, the number of _____________
dots on an isolated atom indicates where covalent
bonds can form.
• Atoms tend to form bonds in such a way as to satisfy
the ______________, having a stable electron configuration
of _________ electrons in their outermost shells.
– _____________ is an exception, since it is in row 1 and
only has the 1s orbital available in the ground
state
Formation of Ionic Solids
• When an element which gives up electrons easily
comes in contact with an element that accepts an
electron easily an electron may be transferred,
yielding a ________________________.
.
Draw Lewis structure for these examples:
Magnesium and oxygen
Aluminum and chlorine
Sodium and oxygen
Lewis Structures
Important terminology
________________________ – a pair of electrons that are
shared between two atoms forming a covalent or polar
covalent bond
_____________________________ – Electron pairs in a
Lewis structure that are not involved in bonding
__________________ – the observation that atoms of
nonmetals form the most stable molecules when they are
surrounded by eight electrons (to fill their valence orbitals)
Lewis Structures
Steps for Writing Lewis Structures
Step 1: Obtain the sum of the valence electrons from
all of the atoms. Do not worry about keeping track
of which electrons come from which atoms. It is
the total number of valence electrons that is
important
Step 2: Use one pair of electrons to form a bond
between each pair of bound atoms. For
convenience, a line (instead of dots) is often used
to indicate each pair of bonding electrons
Step 3: Arrange the remaining electrons to satisfy
the duet rule for hydrogen and the octet rule for
each second row element.
Chapter 12 Vocabulary
 Bond
 Bond
Energy
 Ionic Compound
 Covalent Compound
 Polar Covalent Compound
 Electronegativity
 Lewis Structure
Duet Rule
Octet Rule
Bonding Pair
Lone Pairs
Single Bond
Double Bond
Triple Bond