Chemical Bonding
Atoms lose, gain, or share electrons to have an ________________ (________) in its outer energy level.
Types of Bonding: _____________________,__________________________, _____________________
Ionic Bonding: __________________of electrons
Metal (________ ______) forms a ______ ion
nonmetal (_______ e-) forms a _____________ ion
Ex: NaCl, KBr, KNO3
Ionic Bonding Example: Na and Cl
In ionic bonding one atom has a stronger attraction for electrons than the other, and “steals” an electron from a
second atom
Properties of Ionic Compounds
 Crystalline solids
 High melting point
 Brittle
 Conducts electricity in molten form and when dissolved in water
 Forms a crystal lattice
 Held together by electrostatic attraction (opposite charges)
EX: Sodium and Chlorine
Calcium and Chlorine
Potassium and Sulfur
Covalent Bonding: ____________ e-, _____________________ only Ex: H2O, CCl4
Electronegativity- Measure of the attraction for a shared electron.
Which family would have the highest electronegativity? _________
Which element would have the highest electronegativity? ________
Two types of covalent bonds
Nonpolar bond- share e- _______________ Ex:
Polar bond- ______________ sharing of e-, 2 different nonmetals Ex:
Electronegativity Difference : Used to determine if a bond is ionic or covalent
Atoms that have electronegativity differences ___________ than 1.7 form ionic bonds. Ex: Na-Cl
If the difference is 0 to 0.4 the bond is ________________ covalent. Ex: Cl2.
Atoms that have electronegativity differences less than _______ and greater than _______ form polar covalent
bonds. Ex: H-O
The greater the electronegativity difference the _____________ polar the bond will be.
Electronegativity Difference
0-----------------0.4---------------------1.7---------------EX: Classify as polar, nonpolar, or ionic.
1. P-Cl ____________________________2. Cl-Cl ____________________________
3. Ca-F _____________________________
Polar Bonds
Partial positive charge
Polar, Nonpolar and Ionic Bonds
PROPERTIES OF COVALENT COMPOUNDS
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Solids, liquids and gases
Lower melting points than ionic compounds
Nonconductors (nonelectrolytes)
All nonmetals
Ex: C12H22O11 (solid) H2O (liquid) CO2 (gas)
Covalent Bonding
Octet rule- atoms form bonds to have ________ valence electrons
Exception: H (______ e- )
B (_________ e-)
Lewis Dot Structures
1) F2
2) H2
4) CH4
5) NH3
7) N2
8) CO2
3) H2O
6) O2
MATH METHOD
1.
2.
3.
4.
Count the ___________ # of e- needed to satisfy the octet rule. (NEED)
Count the total # of ____________ e- (HAVE)
________________ #2 from #1 and divide by 2. This equals # bonds.
Make sure every atom obeys the _______________ rule.
9) SO3
12) OCS
10) PO4-3
11) SiH4
13) NF3
BOND ENERGY – energy required to _________________a bond.
Triple bond has the _____________ bond energy and a single bond has the ____________ bond energy.
Triple bond has the _____________ bond length and a single bond has the ____________ bond length.
Resonance
Resonance Structures- occur when more than 1 Lewis structure can be drawn for a molecule.
Ex: CO3-2
SO2
Exceptions to the octet rule:
H ______ B_______ Be __________
Expanded Octet: _______than 8 e- on the central atom (Honors)
Examples (Honors)
Ex: PCl5
SF6
MOLECULAR SHAPES
VSEPR MODEL
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Bonds are made up of eBonds ________________ each other
Bonds will ___________________out around the central atom to be as far apart as possible
Lone pairs of electrons repel ______________than bond repel each other
Count the number of bonded atoms and the number of lone pairs on the CENTRAL atom to determine the
shape.
Molecular Shapes
1. Two atoms bonded to central atom. Can be single, double, or triple bonds.
Ex: BeH2
Shape: _________________
Bond angle: ______________
2. Three atoms bonded to central atom.
Ex: BH3
Shape: _________________
Bond angle : _______________
3. Two atoms and one or two lone pairs on the central atom.
Ex. H2O
Shape: ________________
Bond angle: ______________
4. Three atoms and one lone pair on the central atom.
Ex: NH3
Shape: ________________
Bond angle: _______________
5. Four atoms around the central atom.
Ex: CH4
Shape: ________________
Bond angle: ________________
(Honors) Additional Shapes
6. Five atoms around the central atom.
Ex: PCl5
Shape: ________________
Bond angle: ________________
7. Six atoms around the central atom.
Ex: SF6
Shape: ________________
Bond angle: _________________
Polarity of Molecules
Nonpolar Molecule- _____________ distribution of electrons. _______________ around the central atom. Must
be the same atom around the central atom.
Polar Molecule – _______________electron distribution. Not ____________________ around the central atom.
Hybridization (Honors)
Examples:
1. Be in BeCl2
2. B in BCl3
3. C in CH4
4. P in PCl5
5. S in SF6
How to Determine Hybridization COUNT THE ELECTRON GROUPS AROUND AN ATOM
DOMAINS- # OF ATOMS BONDED TO A CENTRAL ATOM + # UNSHARED PAIRS OF ELECTRONS
MOLECULAR
SHAPE
NUMBER OF
ELECTRON PAIRS
(DOMAINS)
HYBRIDIZATION
EXAMPLES
linear
trigonal planar
bent
tetrahedral
bent
trigonal pyramid
trigonal bipyramid
octahedral
Metallic Bonding
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Occurs in metals
Sea of ________________ electrons that can move around the crystal (__________________ electrons)
Metals are good conductors of heat and electricity