Chapter 11 Chemical Bonds
Objectives
• 11.1 Describe how a compound differs from
the elements that compose it
• 11.1 Explain what a chemical formula
represents
• 11.1 State a reason why chemical bonding
occurs
Objectives
• 11.2 Describe ionic and covalent bonds
• 11.2 Identify the particles produced by ionic
bonding and by covalent bonding
• 11.2 Distinguish between a polar and
nonpolar covalent bond
Objectives
• 11.3 Describe the dangers posed by hazardous
compounds in the home
• 11.3 Demonstrate a knowledge of a safer
alternative of compounds to use
• 11.4 Explain how to determine oxidation
numbers
Objectives
• 11.4 Write formulas for compounds from their
names
• 11.4 Name compounds from their formulas
• 11.4 Describe hydrates and their formulas
Introductory
• Elements will have very different properties
than the compounds they are in
– Examples: Oxygen = Flammable, Gas at Room
Temperature
– Hydrogen = Flammable, Gas at Room Temperature
– Water (A compound of above) = Puts out fire,
liquid at room temperature
– Many others, consider table salt
Why do Elements come together?
• To complete their outer shell
– Have a noble gas configuration
• Elements which have a full outer shell tend to
be chemically stable (unreactive)
• A full outer shell consists of 8 valence
electrons
– In the case of metals, losing all of their valence
electrons
23
BONDING
Bonds Between Atoms
Polyatomic Ions
Ionic
Covalent
Molecular
Substance
Metallic
Network
Solids
Polar
Nonpolar
What are we going to learn about???
Coordinate
Covalent
Important Words (Ie On Quiz)
• Anion- negative ion
• Cation-positive ion
• Octet Rule- rule that states that atoms tend to gain, lose,
or share electrons so that each atom has full outermost
energy level which is typically 8 electrons.
• Polyatomic Ion- charged group of covalently bound
atoms
• Polar-means ‘uneven’ sharing
• Molecule-neutral group of atoms united by covalent
bonds
• Hydrate-molecule surrounded by water
• Oxidation number-number of electrons lost or gained
• Covalent Bond- formed between 2 nonmetals
Ionic Bonds
•What is an Ionic Bond?
-An Ionic Bond is a chemical bond
resulting from the TRANSFER of electrons
from one bonding atom to another
-It is composed of positive and negative
atoms or particles
• When is an ionic bond formed?
- An ionic bond is formed when a Metal
and Non-Metal come together
What are some characteristics of an ionic
bond?
1.
Crystalline at room
temperatures
2. Have higher melting
points and boiling
points compared to
covalent compounds
3. Composed of Positive
and Negative Charges,
but do NOT conduct
electricity
1.
Corrosion stops
batteries
Covalent Bonds
•What is an Covalent Bond?
- A covalent bond is a chemical bond
resulting from SHARING of electrons
between 2 bonding atoms.
• What forms a covalent bond?
- A covalent bond is formed between two
nonmetals.
What are some characteristics of a covalent
bond?
1.
2.
3.
Covalent bonds have
definite and predicable
shapes.
Low melting and boiling
points
Is a molecule
Molecules
• Composed of COVALENT Bonds
– Electrons are shared
• Not all elements share equally though
– Polar Molecules: Uneven sharing
• Have a Positive and Negative side
• If you have different elements, will have a Polar Bond
• IE If Carbon and Oxygen make a bond, it will be polar
– Non-Polar Molecules: Even Sharing
• Same element, IE Oxygen
Chemical Formulas
• Chemical Formulas tell us how many of each
element are in a compound
– A ratio for salts (ionic compounds) and an actual
number for molecules.
•
•
•
•
NaOH = 1 Na, 1 O, 1 H
H2O = 2 H, 1 O
Mg(NO3)2 = 1 Mg, 2 N, 6 O
2 CO2 = 2 C, 4 O
+1+2
Ionic Charges
-3 -2 -1
Formulas of Ionic Compounds
Formulas of ionic compounds are determined from
the charges on the ions
atoms
Na  +

 F

: 
sodium + fluorine
Charge balance:
ions
 –
Na+ : F :  NaF

sodium fluoride
formula
1+
= 0
1-
Writing a Formula
Write the formula for the ionic compound that will
form between Ba2+ and Cl.
Solution:
1. Balance charge with + and – ions
2. Write the positive ion of metal first, and the
negative ion
Cl
Cl
Ba2+
3. Write the number of ions needed as
subscripts
BaCl2
Ionic Nomenclature
•
•
•
•
•
•
•
What is the formula of the following?
Potassium Oxide
K2O
Strontium Chloride
SrCl2
Magnesium Nitride
Mg3N2
Ionic Nomenclature
• Potassium Phosphide
• K3P
•
•
•
•
Magnesium Sulfide
MgS
Radium Flouride
RaF2
Ionic Nomenclature
• Binary Compounds of Metals with Fixed Charges:
Given Formula, Write the Name
• The order for names in a binary compound is first the
cation (Metal), then the anion (Non-Metal).
• Use the name of cation with a fixed oxidation state
directly from the periodic table.
• The name of the anion will be made from the root of
the element's name plus the suffix "-ide."
Practice Naming
•
•
•
•
•
•
•
What is the name of the following?
MgO
Magnesium Oxide
NaF
Sodium Flouride
CaS
Calcium Sulfide
Transition Metals
Elements that can have more than one possible charge
MUST have a Roman Numeral to indicate the charge
on the individual ion.
1+ or 2+
Cu+, Cu2+
2+ or 3+
Fe2+, Fe3+
copper(I) ion iron(II) ion
copper (II) ion iron(III) ion
Variable Charges
• Formula to Name
• 1) Find the charge of the cation by
– Finding total charge of anion and dividing by
number of cations
• Example: FeCl3
– We have 3 Chlorines, each has a -1 charge
– The Fe needs to be +3 to balance it out
• 2) Say the cation with its Roman Numeral
– Iron (III) Chloride
Variable Charges
• What is the name?
• AuF3
•
•
•
•
•
Gold (III) Flouride
AgF
Silver (I) Flouride
PbO2
Lead (IV) Oxide
Variable Charges
•
•
•
•
•
•
•
•
SnF2
Tin (II) Flouride
MnO2
Manganese (IV) Oxide
CrN
Chromium (III) Nitride
Sn3N4
Tin (IV) Nitride
Variable Charges
•
•
•
•
Name to Formula
The Roman Numeral tells you the charge
Balance the formula
Iron (III) Oxide
– Fe has a +3 charge as denoted by the III
– Oxygen always has a -2 charge
– Cross them (Balance)
– Fe2O3