chapter 2: molecules, ions, and compounds macroscopic scale elements combine to make compounds....

Chapter 2: Molecules, Ions, and Compounds

MACROSCOPIC SCALE

Elements combine to make compounds.

ATOMIC SCALE

Atoms combine to make molecules, or extended structures.

What we’ll cover…• Compound Formulas

• Ions– Monatomic– Polyatomic

• Ionic Compounds

• Molecular Compounds

• Other types of extended Structures

Compound Formulas

Examples:

NaCl

CH3OH

(NH4)2SO4

Three Types of Compounds

Molecular Covalent Extended Covalent

Ionic

Types of Formulas

IONS

Cations

Formed by losing electrons.

Have a positive charge.

Formed mainly from metals.

IONS

Cations

Formed by losing electrons.

Have a positive charge.

Formed mainly from metals.

Anions

Formed by gaining electrons.

Have a negative charge.

Formed mainly from nonmetals.

Monatomic Ions- Formed from single atoms

Naming IONS

Cations

Name of element + “ion”

Na+ = sodium ion

Mg2+ = magnesium ion

Naming IONS

Cations

Name of element + “ion”

Na+ = sodium ion

Mg2+ = magnesium ion

Anions

Name of element with –ide ending + “ion”

Cl- = chloride ion

O2- = oxide ion

Polyatomic Ions you need to know

Ionic Compound Formulas

Total cation charge = Total anion charge

Ex: Na+ and Cl- make ________

Ionic Compound Formulas

Total cation charge = Total anion charge

Ex: Na+ and Cl- make NaCl

Mg2+ and Cl- make ________

Ionic Compound Formulas

Total cation charge = Total anion charge

Ex: Na+ and Cl- make NaCl

Mg2+ and Cl- make MgCl2

NH4+ and SO4

2- make _________

Naming Ionic Compounds

Name = cation name + anion name

Ex:

NaCl =

NH4Br =

Molecular Compounds

Nonmetal + nonmetal gives molecular compound

Ex: C + O

S + O

C + H

Aside on gas prices…

Crude oil

Propane

Butane

Jet Fuel

Gasoline

Diesel/Heating

Longer molecules(asphalt/tar)

Predicting Molecular Compound Formulas

Naming Molecular Compounds

Binary Compounds form between 2 elements

Naming Molecular Compounds

Binary Compounds form with 2 elements

Element with highest group # named last, like it’s an anion.

Naming Molecular Compounds

Binary Compounds form with 2 elements

Element with highest group # named last, like it’s an anion.

Use prefixes to indicate numbers:2 = di3 = tri4 = tetra5 = penta

Network Solids

• Held together like a molecule

• Large and extended