Bonding Notes Page | 1

Unit 5b: Bonding and Shape

(Link to Prentice Hall Text: Chapters 15 & 16)

Date Due / Assignments / Page Number: Problem Numbers
Assignment 1: Ionic Bonding / 432: 23, 25, 26, 44
470: 53
Assignment 2: Covalent Lewis Structures / 470: 30, 32, 33, 37, 38, 41
Assignment 3: Molecular Geometry, Sigma + Pi / 470: 47, 48, 63
Assignment 4: Hybridization / 470: 50, 66
Assignment 5: Polarity / 470: 52, 54
Assignment 6: Coordinate Covalent Bonds / 470: 34
Assignment 7: Metallic Bonding / 432: 39
Assignment 8: Intermolecular Forces / 470: 55, 56, 57, 58

A.  What is a Chemical Bond?

The Nature of the Chemical Bond

A chemical bond is best described as an ______.

Chemical bonds are created due to forces between ______and ______within an atom.

______to break a chemical bonds, ______. It is an ______process.

When a chemical bond forms,______. It is an ______process.

B.  Valence Dot Structures for Atoms

Valence Number Periodicity

Group
Period / 1 / 2 / 13 / 15 / 16 / 17
2
Ion
3
Ion

C.  Properties of Ionic Compounds

Ionic Dot Structures

1.  Why do metals tend to lose electrons and non-metals tend to gain electrons?

Metals: ______

Non-metals:______

2.  What electron configuration does each atom attain in an ionic compound?

Each atom attains the electron configuration of a ______

Ionic Dot Structures
When writing Lewis Diagrams for ionic compounds, simply show the Lewis Dot Structure for each individual ion (include charge), and put the atoms in brackets. Draw the Lewis Diagram for each of the following ionic compounds.

1.  NaCl Name: / 2.  LiF Name:
3.  CaO Name: / 4.  MgS Name:
5.  MgCl2 Name: / 6.  CaI2 Name:
7.  RbBr Name: / 8.  SrF2 Name:


Lewis Diagrams for Covalent Compounds

The bonds for covalent compounds do not involve the transfer of electrons. Covalent compounds involve the sharing of electrons.

Vocab

Lone pair-

Single covalent bond-

Double covalent bond-

Triple covalent bond-

Resonance-

General Guidelines for Drawing Lewis Diagrams for Covalent Compounds

Step 1: Count the total number of valence electrons.

Step 2: Assemble the bonding framework (skeleton). Place the most electronegative element in the center.

Step 3: Arrange the remaining electrons so that each atom has 8 electrons around it (the octet rule). If necessary, place additional pairs of electrons between the atoms to form additional bonds.

Step 4: Check for exceptions to the octet rule.

Step 5: Evaluate whether the formal charges (FC) on the atoms are reasonable.

Step 6: If necessary, draw resonance structures.

Formal Charge =

Drawing Lewis Structures with Simple Single, Double and Triple Bonds

Use the rules above to draw Lewis structures for the following compounds.

1.  CH4
Molecular Geometry:______/ 2.  H2S
Molecular Geometry:______
3.  PH3
Molecular Geometry:______/ 4.  NH3
Molecular Geometry:______
5.  H2O
Molecular Geometry:______/ 6.  SF4
Molecular Geometry:______
7.  C2H4
Molecular Geometry:______/ 8.  OH-
Molecular Geometry:______
9.  CH3Br
Molecular Geometry:______/ 10.  CO32-
Molecular Geometry:______
11.  C2H3Cl
Molecular Geometry:______/ 12.  CO2
Molecular Geometry:______
13.  SO3
Molecular Geometry:______/ 14.  N2O
Molecular Geometry:______
15.  XeF4
Molecular Geometry:______/ 16.  NO3-
Molecular Geometry:______
17.  SCN-
Molecular Geometry:______/ 18.  C3H8
Molecular Geometry:______
19.  NI3
Molecular Geometry:______/ 20.  BF3
Molecular Geometry:______

D.  Summary of Hybridization and Molecular Geometry

Central Electron Pairs / Electron Geometry / Number of Bonds / Bond Angles / Molecular Geometry / Shape / Hybridization
2 / Linear / 2
3 / Trigonal planar / 2
3 / Trigonal planar / 3
4 / Tetrahedral / 2
4 / Tetrahedral / 3
4 / Tetrahedral / 4
5 / Trigonal bypyramidal / 2
5 / Trigonal bypyramidal / 3
5 / Trigonal bypyramidal / 4
5 / Trigonal bypyramidal / 5
6 / octahedral / 2
6 / octahedral / 3
6 / octahedral / 4
6 / octahedral / 5
6 / octahedral / 6

E.  Three-Dimensional Representations of Covalent Compounds

The following are VSEPR (Valence Shell Electron Pair Repulsion) geometries for covalent compounds. VSEPR is based on the idea that regions of electrons (either lone pairs or bonds) will repel to seek the configuration where they are the furthest apart, and therefore the most stable.

F.  Hybridization of Orbitals

Valence Bond Theory (Linus Pauling) – In order for atoms to bond, orbitals must overlap.

sp Example: BeCl2
sp2 Example: BF3
sp3 Example: CH4

G.  Sigma and Pi Bonds


Determining Number of Sigma and Pi Bonds

Single Bonds Consist of: ______

Double Bonds Consist of:______

Triple Bonds Consist of:______

H.  Bond Polarity and Molecular Polarity

Determining the Polarity of a Bond

If two atoms, with a bond between them, have different electronegativities, the bond is described as ______.

Polar covalent bonds have an end that is partially ______and partially ______in charge. A polar bond is said to have a ______.

Nonpolar covalent bonds have no charge separation.

Scale:


Determining the Polarity of a Compound

If a molecule is symmetrical, the molecule is ______.

If a molecule is nonsymmetrical, the molecule is ______.

Determining Molecular Polarity

Draw the Lewis Structures for the following compounds and determine whether they are polar or nonpolar. Important: Place lone pairs on the same atom adjacent to each other.

1.  HCl / 2.  CO2
3.  CCl4 / 4.  H2O
5.  O2 / 6.  C2HCl
7.  HCN / 8.  C2H4

J.  Compounds Containing Ionic and Covalent Bonds

Identifying Compounds with Ionic and Covalent Bonds

Ionic compounds that contain ______ions contain both ionic and covalent bonding.

1.  Sodium nitrate / 2.  K3PO4
3.  KNO2 / 4.  Ammonium chloride

K.  Coordinate Covalent Bonds

Identifying Coordinate Covalent Bonds

In some cases one atom donates all of the electrons to a bond. In this case, it is called a coordinate covalent bond.

Example 1: NH4+ / Example 2: H3O+

L.  Intermolecular Forces: Influence on Vapor Pressure and Boiling Points

Three Types of Intermolecular Forces

Intramolecular forces:

Intermolecular Forces:

As forces of attraction between molecules increase, the:

(1)  Vapor Pressure ______

(2)  Boiling Point ______

A.  Intermolecular Force (1): Hydrogen Bonding Force - STRONGEST

Occurs only between molecules that have a ______atom bonded to a fluorine, oxygen or nitrogen atom.

B.  Intermolecular Force (2): Dipole-Dipole Force - INTERMEDIATE

Occurs between ______molecules.

C.  Intermolecular Force (3): Dispersion (van der Waals) Force - WEAKEST

Occurs between ______molecules. As the mass of the molecule/atom increases, the van der Waals forces.

M.  Distinguishing Ionic, Metallic, Molecular and Covalent Network Solids

Differences in Bond Type in Various Solids

Example / Picture / Properties
Ionic Solid
Metallic Solid / Metals are atoms that have low ionization energies and a small number of valence electrons. The inner electrons of metal atoms are arranged in a crystalline lattice. The valence electrons move freely throughout the lattice and are not attached to any one atom in particular.
Molecular Solid
Covalent Network Solid