Chapter 2: Molecules, Ions, and Compounds
MACROSCOPIC SCALEElements combine to make compounds.
ATOMIC SCALEAtoms 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
CationsFormed by losing
electrons.Have a positive
charge.Formed mainly
from metals.
IONS
CationsFormed by losing
electrons.Have a positive
charge.Formed mainly
from metals.
AnionsFormed by
gaining electrons.
Have a negative charge.
Formed mainly from nonmetals.
Monatomic Ions- Formed from single atoms
Naming IONS
CationsName of element + “ion”Na+ = sodium ionMg2+ = magnesium ion
Naming IONS
CationsName of element + “ion”Na+ = sodium ionMg2+ = magnesium ion
AnionsName of element with
–ide ending + “ion”Cl- = chloride ionO2- = 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 NaClMg2+ and Cl- make ________
Ionic Compound Formulas
Total cation charge = Total anion charge
Ex: Na+ and Cl- make NaClMg2+ 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
