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