Module 1 Chemical Bonding and Molecular Geometry
CHEM-1312 M1L1 Explore: Chemical Bonding and Molecular Geometry
In this module, you will learn to identify different types of geometries (LO1.1.1). In this lesson, you will learn about chemical bonds through an introduction to Lewis dot symbols, which shows the valence electrons on an atom.
Overview
What This Lesson Is About
Review of chemical bonding and Molecular Geometry.
What You Will Learn
- Our study of chemical bonds begins with an introduction to Lewis dot symbols, which shows the valence electrons on an atom. (9.1)
- We then study the formation of ionic bonds and learn how to determine lattice energy, which is a measure of the stability of ionic compounds. (9.2 and 9.3)
- Next we turn our attention to the formation of covalent bonds. We learn to write Lewis structures, which are governed by the octet rule. (9.4)
What to Read
Overby/Chang: Chemistry, 14th Ed. - Chapter 9
Media
The Ionic Bond
Ionic bonds occur between a metal and a non-metal. Unlike covalent bonds, ionic bonds transfer their valence electrons between atoms.
Time: 5:48 min.
Topic: What is an ionic bond?
Lattice Energy: Born Haber Cycle
The Born Haber process, more commonly referred to as the Born Haber cycle, is a method that allows us to observe and analyze energies in a reaction.
Time: 10:05
Topics: Lattice Energy: Born Haber Cycle
Lattice Energy
The Lattice energy, U, is the amount of energy required to separate a mole of the solid (s) into a gas (g) of its ions.
Time: 11:24
Topics: Lattice Energy
Covalent Bond
The term covalent bond is used to describe the bonds in compounds that result from the sharing of one or more pairs of electrons.
Time: 8:42
Topics: Covalent Bond
Lewis Structures
A Lewis structure is a graphic representation of the electron distribution around atoms.
Time: 5:12
Topics: Lewis Structures
Bond Length and Bond Types
Bond length is defined as the distance between the centers of two covalently bonded atoms. The length of the bond is determined by the number of bonded electrons (the bond order). The higher the bond order, the stronger the pull between the two atoms and the shorter the bond length.
Time: 7:15
Topics: Bond Length and Bond Types
Intramolecular vs Intermolecular
Intramolecular forces are those within the molecule that keep the molecule together, for example, the bonds between the atoms. Intermolecular forces are the attractions between molecules, which determine many of the physical properties of a substance.
Time: 2:19
Topics: Intramolecular vs Intermolecular
Electronegativity Examples
Time: 11:40
Topics: Electronegativity Examples
Supplemental Resources
An extremely flexible and informative periodic table: Periodic table
Periodic Table: Offline Version
How to Draw Lewis Valence Electron Dot Structures
Molecular Polarity
In this activity you will use a PhET simulation to explore molecule polarity.
One Atom
What factors affect molecule polarity?
Explore the Molecule Polarity simulation for a few minutes with a partner. In each of the three tabs, try to find all of the controls and figure out how they work.
Two Atoms
Describe all of the ways you can change the polarity of the two-atom molecule.
Explain how the representations below help you understand molecule polarity.
☑ Bond Dipole
☑ Partial Charges
◉ Electrostatic Potential
◉ Electron Density
Three Atoms
Describe any new ways you can change the polarity of the three-atom molecule.
Explain the relationship between the bond dipoles and the molecular dipole.
credit: PhET, phet.colorado.edu, Molecular Polarity
Can a non-polar molecule contain polar bonds? Explain your answer with an example.