Bonding Lesson Part 2

​Bonding Notes Part 2

Objective 6: COVALENT BONDING

A.

Nonpolar-covalent Bonding

1.

Electronegativity difference ranges from 0 to ≤ 0.3

2.

Involves equal sharing of electrons

B.

Polar-covalent Bonding

1.

Electronegativity difference ranges from 0.3 - 1.7

2.

Invoves unequal sharing of electrons

If the difference is greater than or equal to 1.7 it is IONIC.

Objective 7: Covalent Lewis Dot Diagrams

Example: Draw the Lewis structure for I2 (iodine).

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1. Determine the type of bond from the electronegativity difference.

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2. Determine the number of valence electrons.

Objective 7: Covalent Lewis Dot Diagrams

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Example: Draw the Lewis structure for NH3 (ammonia).

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Determine the type of bond from the electronegativity difference.

Multiple Choice

What two types of atoms make a covalent bond?

• 2 non-metals

• 1 metal and 1 non-metal

• 2 metals

Multiple Choice

What type of bond involves the sharing of electrons between atoms?

• covalent bond

• ionic bond

• metallic bond

• transfer bond

Objective 8: MULTIPLE BONDS

(APA: also see additional notes for drawing Lewis structures, multiple
bonds, bond order, resonance, polyatomic ion structures, and formal
charge)

A. single bond- one shared pair of electrons between two atoms

B. Multiple bonds- more than one electron pair is shared, seen in molecules
containing carbon, oxygen, and nitrogen

►double bond- the sharing of two electron pairs

►triple bond- the sharing of three electron pairs

Objective 9: VSEPR THEORY

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Valence Shell Electron Pair Repulsion Theory - explains why molecules
take the shapes they do. When forming a compound, bonding and
nonbonding electron pairs around a given atom will position themselves as
far apart as possible .

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Electron Pair Repulsion

►Strongest Repulsion occurs between two unshared pairs.

►Medium Repulsion occurs between one unshared and one shared pair.

►Weakest Repulsion occurs between two shared pair

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Pre-AP: Hybridization-the mixing of two or more orbitals to create
orbitals of equal energy. The number of hybrid orbitals created equals the
number of orbitals that have blended.

VSEPR- Molecular shape and polarity

*Pre-AP: Also see additional notes for intermolecular attractions

Objective 10: COMPOUND POLARITY

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Use electronegativity and bonding arrangement to determine whether a
compound is polar or nonpolar.

Objective 10: COMPOUND POLARITY

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Symmetrical compounds are nonpolar.

Objective 10: COMPOUND POLARITY

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Compounds that contain an unshared pair of electrons or are not
symmetrical are polar.

Objective 11: COMPARISON OF
IONIC AND MOLECULAR
COMPOUNDS

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Differences between the properties of ionic and
covalent compounds exist because ionic bonds are much
stronger than covalent bonds.

Objective 11: COMPARISON OF
IONIC AND MOLECULAR
COMPOUNDS

Covalent bonds

A. Properties of ionic
compounds

1.

High melting and boiling points

A. Properties of ionic
compounds

2. Soluble in water, but not in nonpolar liquids

A. Properties of ionic
compounds

3. solids with well-defined, hard crystals; break but do not bend

A. Properties of ionic compounds

4. conduct electricity when melted or dissolved

5. formed between metals and nonmetals and/or polyatomic ions.

B. Properties of compounds
with covalent bonds:

1.

can be solid, liquid or gas; covalent solids are softer
than ionic solids

2. lower melting and boiling points than ionic compounds

3. many are soluble in nonpolar liquids, but not water; while some are
soluble in water

4. nonconductors of electricity in all phases

5. generally formed between nonmetals and other nonmetals

Objective 12: METALLIC
BONDING

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In metals, the valence electrons are delocalized- they
do not belong to one atom, but are free to move
throughout the metal. This model is sometimes referred
to as the electron sea model. Since the metal atoms
have all lost their valence electrons, they are now all
identical positively charged ions, or cations, surrounded
by a sea of electrons.

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Metallic bonds are the attraction of the delocalized valence electrons in
the sea of free-moving electrons for the positively charged metal ions.

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Metallic bonds are very strong, therefore metals have high melting and
boiling points

Properties of metals can be explained by the
electron sea model.

Metals are:

►Thermally and electrically conductive- transfer of heat and electricity
depends on flow of electrons; metals are good conductors of electricity
and heat, because as electrons move in .... electrons move out.

►

Malleable - can be hammered into different shapes

►

Ductile - can be drawn into a thin wire

►

Luster- shine

Multiple Choice

Low melting point and low solubility in water are general properties of ______________________ compounds

• ionic

• covalent

• all

Multiple Choice

Ionic bonds are formed when electrons get

• Shared between two atoms

• Removed from both atoms

• Transferred from one atom to another

• Added to both atoms

Multiple Choice

What type of bond involves the sharing of electrons between atoms?

• covalent bond

• ionic bond

• metallic bond

• transfer bond