Chemical Bonding, Compounds
and Nomenclature
AEA Ismail
Learning Objectives
After this section you should be able to :
1. Predict the type of bond formed within a compound
2. Give the correct chemical formula for compound
3. Compare and Contrast Ionic and Covalent bonding and the resulting
comounds.
4. Give the correct chemical name for a given chemical formula
Bonding
• All chemical reactions create or break bonds. When bonds are made
and broken energy is either needed or required.
• Review : A chemical change is a change that involves the creation of
new matter. When new matter is created bonds have to be either
broken or created or both.
• Why do you think atoms want to bond?? What particles found in the
atom are involved in bonding?
Bonding
• Bonding is all about ELECTRONS
• There are two ways in which bonds can form:
1. Transferred – Ionic Bonding
2. Shared - Covalent Bonding
Atoms bonds because they want to get a full outer
shell(Octet Rule – 8 electrons)
Ionic Bonding
Ionic Bonding is when electrons are transferred between two atoms.
• Usually occurs between a metal and a non-metal
• Forms a three-dimensional lattice
How to determine the Chemical Formula of
an Ionic Compound
• Step 1: you have to determine the charge of the individual elements involved, for
instance if we have Al and Cl.
• Al=+3
Cl=-1
• Step 2 : Crossing the numbers. This means that you take the 3 from the Al and put it as
the subscript for Cl and the 1 from Cl and put it as the subscript for Al. Then you get rid of
the charges.
• Chemical Formula : AlCl3
A chemical formula is the way of expressing the proportions of the atoms within the
molecule/compound.
For instance, above there are 3 Chlorines for every 1 Aluminum.
Why you may ask?
Why does it form AlCl3
Naming Ionic Bonded Compounds
• Step 1:identify if the compound is an ionic compound. If it does then
it is an ionic compound.
• Step 2: Write down the metal first followed by the non-metal, but you
change the ending of the non-metal to –ide.
• For example – CsF - Cesium Floride
•
MgO – Magnesium Oxide
•
Ca3P2- Calcium Phosphide
Ionic Formula Practice
Predict the formula for the following :
1. Aluminium Phosphide
2. Gallium Sulfide
3. Sodium Oxide
4. Barium Fluoride
5. Potassium Chloride
Predict the Name of the Following
Compounds
• Identify the Chemical name for the following compounds :
1. AlS
2. In2O3
3. Cs2Se
4. Mg0
5. CaCl2
Covalent Bonding
• Covalent Bonding is when electrons are shared between two atoms.
• Occurs between two non-metals
• Forms small individual molecules to three-dimensional lattices
• Depends on the atoms involved and the arrangement
Carbon vs Diamond
These two covalent
compounds have the
same chemical
formula, but different
structures. Graphite
has a molecular
structure, while
diamond has a threedimensional lattice
structure
How to Name a Covalent Bonded Molecule
Step 1 : Identify whether the compound is ionic or covalent. If it is
covalent right down what you have, but change the ending of the
second non-metal to –ide.
Step 2: Add Prefixes before the elements to symbolize how many of
each element we have. (Note, mono is not used for the first element)
Ex.. CO3 – Carbon Trioxide
S2O3 – Disulfur Trioxide
Covalent Naming Practice
Name the following
1. NO2
2. C2S5
3. PO
4. Se2O3
5. C5H8
Predict the Chemical Formula
What is the chemical formula for the following?
1. Tetracarbon Monohydride
2. Disulfur Trifloride
3. Nitrogen Trihyride
4. Carbon Manoxide
5. Sulfur dioxide
Drawing Simple Diatomic Covalent Bonded
Molecules
• Please Draw a molecule of O2
Simplified Rules for Drawing Simple Covalent
Molecules (More complex rules in chemistry)
All the molecules you will draw are diatomic molecules of the same element.
1. Draw the outer shell (valence electrons) of the atoms involved.
2. A covalent bond involves the sharing of two electrons, 1 by each atom.
Therefore, every time one atom shares the other atom has to share.
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3. For each pair of shared electrons we draw a bond, which is a line. To
determine how many shared electrons we think about how many electrons
it takes to fill up the outer shell.
Therefore atoms share electrons until both atoms are happy enough and
their outer shells are full.
Draw F2
Draw N2