Tuesday, January 22, 2008• Final Grades• Quick Review

• Electron configurations• Types of bonding• Ions and Ionic Compounds

• Lewis Structures

QUIZ FRIDAY

•Homework for TuesdayPage 436, #18, 20a,d,e, 21-22, 23a,b, 24-27, 28a,b,c, 29Homework for WednesdayPage 436, #30-38Lewis Structures Activity WS

Electron ConfigurationsElectron ConfigurationsGive the electron configurations for the

following elements:

Sodium

Sulfur

Carbon

What about for these ions?

Sodium ion (Na+)

Aluminum ion (Al3+)

Types of BondingTypes of BondingIonic Bonding -

Covalent Bonding -

Polar Covalent Bonding -

The attraction between ___________________Between __________ and ________Involves ____________ of electrons

A type of bonding in which atoms ____________ electronsBetween two ______________Involves _________ of electrons equally

A ___________ bond in which the electrons are ______ shared equally because one atom attracts the shared electrons _________ than the other atom

Ions & Ionic CompoundsIons & Ionic Compounds

Charges on IonsGroup 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 Characteristics of Ionic CompoundsCompounds

High Melting PointConduct electricity (when dissolved in water)

Valence ElectronsValence 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 – 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 StructuresLewis 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

Lewis StructuresLewis Structures

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 oxygenAluminum and chlorineSodium and oxygen

Lewis StructuresLewis StructuresImportant 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 StructuresLewis StructuresSteps for Writing Lewis StructuresStep 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 VocabularyChapter 12 VocabularyBondBond Energy Ionic CompoundCovalent CompoundPolar Covalent CompoundElectronegativityLewis Structure

Duet RuleOctet RuleBonding PairLone PairsSingle BondDouble BondTriple Bond