1. Grade 9/10 Chemistry Review
Ms. Richardson
SCH3U/4C

2. Safety in the Laboratory
Always wear protective clothing when using materials that could shatter or splash
Goggles, lab coat, etc.
Be aware of the safety equipment that is available and where they are located
Fire blanket, fire extinguisher, eye-wash station
Know the proper procedures for using safety equipment

3. Safety in the Laboratory
Follow instructions for proper disposal of broken glass and chemicals
WHMIS (Workplace Hazardous Materials Information System) symbols are used in Canada to identify dangerous materials

4. The Atom The atom is the basic unit of a chemical element.
Atoms are indivisible, and are made up of 3 subatomic particles:
Positive protons (p+)
Neutral neutrons (n0)
Negative Electrons (e-)

5. Compounds & Molecules
Two or more different atoms chemically combine to form compounds.
A molecule is the smallest form of any element or compound that has the properties of that substance.
Diatomic molecules are molecules composed of 2 atoms of the same element. There are 7 diatomic molecules.

6. Chemical Symbols
Every element has a unique chemical symbol that is universally recognized
The chemical symbol for an element is typically made up of 1-2 letters
Only the first letter of the chemical symbol is upper case
You should be familiar with the names and symbols for the first 20 elements

7. Standard Atomic Notation
We can describe elements through standard atomic notation

8. Chemical Changes
During chemical reactions, a new substance is produced. The properties of the new substance(s) will differ from the properties of the original substance(s).
Evidence that a chemical change has occurred:
Gas forms (bubbles/fizzing)
Precipitate (solid) forms from two liquids
Heat is released/absorbed
Light is produced
The colour changes

9. Ionic Compounds
An ionic compound forms when one or more electrons are transferred from a metal to a non-metal atom.

10. The Octet Rule
Atoms tend to combine in such a way that each atom has eight electrons in its valence (outermost) shell.
This is accomplished through one of two ways:
The transfer of electrons (ionic compounds)
The sharing of electrons (covalent/molecular compounds)

11. Ionic Compounds
Ionic compounds form when one or more electrons are transferred from a metal atom to a non-metal atom.
Atoms that lose electrons become cations (positive ions)
Atoms that gain electrons become anions (negative ions)
The amount of the charge is based on the number of electrons transferred.

12. Polyatomic Ions Ionic compounds can be composed of polyatomic ions.
A polyatomic ion is a group of atoms that act as a single unit and have a charge.

13. Naming Ionic Compounds
Example:
NaCl
sodium
sodium chlor-
sodium chloride
Most ionic compounds can be named by following these steps:
Write the name of the metal.
Next, write the prefix of the non-metal.
Change the ending of the non-metal to –ide.
** What about naming ionic compounds containing polyatomic ions?

14. Writing Formula for Ionic Compounds
The sum of the charges in any ionic compound must equal zero.
We use subscripts to indicate the number of each ion in a compound.
Example: barium chloride
Ba Cl2
(2+) + [2(1-)] = 0

15. Covalent (Molecular) Compounds
Covalent compounds form when electrons are shared between two non-metal atoms.

16. Naming Covalent Compounds
When naming covalent compounds, we use prefixes to indicate the number of atoms of each element.
Example:
P2I4
diphosphorus tetraiodide