compound and molecules. ch.3 PDF

Preview

Summary

compound molecules ch. 3.1-3.5...

Description

Compounds and Molecules     

3.1 3.2 3.3 3.4 3.5

Ionic Compounds Covalent (molecular) Compounds Three-Dimensional Shapes of Molecules Polarity Intermolecular Forces of Attraction

Suggested problems: Practice Exercises: 1-30. End of chapter problems. Only odd: 39, 43-61, 65-89, 93, 97, 101-109, 119-141.

39, 43-61, 65-71 (topics in yesterday’s worksheet)

Let the quality control reassign all three roles in the team. Everyone has a new role. Tackle the Lewis Structure worksheet.

Electron Dots • aka Lewis structures. • Used to predict geometry, hybridization, polarity and more! • Used for covalent structures and polyatomic ions, but they are not good for ionic compound structure.

To Make a Lewis Structure • Count valence electrons taking ionic charge into account. • Cluster the atoms. – Make clusters, not trains. C can make trains. – C in middle, H and F on outside. • Connect the atoms with a bond (two electrons per bond). • Speckle with extra electrons pairs around atoms until you get to your electron sum. • Correct by adding double and triple bonds until you get to 8 electrons around each atom. (2 for H).

Lewis Structure Example • Draw the Lewis structure of

CO32-

Lewis Structure Example • Draw the Lewis structure of

CO32-

Even though it will be covered in lab. Let’s do it here too. Molecular Shape Worksheet.

From Lewis Structure to Electronic Geometry • Groups of electrons repel. • They get as far away as possible. • The groups can be bonds (single, double and triple all count as one group). • The groups can be nonbonding pairs of electrons.

Electronic Geometries

Molecular Geometry • Molecular geometry is an extension of electronic geometry, but you only examine atoms.

What is the electronic geometry?

Bent

Trigonal Pyramidal

Tetrahedral

    

3.1 3.2 3.3 3.4 3.5

Ionic Compounds Covalent Compounds Three-Dimensional Shapes of Molecules. Polarity. Intermolecular Forces of Attraction

Caffeine

molecular formula C8H10N4O2

Structural Formula

Diatomic Gases • There is one more topic worth mentioning when introducing covalent compounds, and that is the diatomic gases. • H2, N2, O2, F2, Cl2, Br2, I2. • Although these compounds are often called by the name of the element, I will strive to distinguish the gas from the element • For example I will call O2 either oxygen gas or dioxygen, and O either an atom of oxygen or oxygen the element. • He, Ne, Ar, Kr, Xe and Ra are monoatomic gases.

    

3.1 3.2 3.3 3.4 3.5

Ionic Compounds Covalent Compounds Three-Dimensional Shapes of Molecules Polarity Intermolecular Forces of Attraction

Caffeine

molecular formula C8H10N4O2

Structural Formula...