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Chemistry Review
Classification of Matter
Chemistry – What is it?
Chemical vs. Physical Change
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Chemical change (or reaction): new substances
with different properties are formed.
Physical change: no new substances are formed.
A change in state or shape is a physical change.
How do you know if a chemical
reaction has occurred?
1)
2)
3)
4)
5)
Formation of a gas
Formation of a precipitate (solid)
Color change
Energy is released (exothermic)
Energy is needed (endothermic)
Please note that with any chemical change,
there is also a change in energy.
Lab Safety
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Recognize hazards!!!!
No book bags or large jackets in the lab
Always wear safety goggles and lab aprons,
especially when working with hazardous
materials and liquids
Do not eat or drink in the lab.
Long hair should be tied up.
Do not have combustible materials near a
flame
Clean up your lab bench once you are done.
Look for WHMIS labels on chemical bottles
(see page 35 in text)
Compressed
gas
Flammable and
combustible material
Oxidizing
material
Materials causing
immediate and
serious toxic effects
Materials causing
other toxic
effects
Biohazardous
infectious material
Corrosive
material
Dangerously reactive
material
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Use safe procedures & techniques
 Tie back long hair
 Always wear safety glasses
 Do not eat or drink in the lab.
 Never taste chemicals
 Do not directly inhale chemicals
 Please stand while doing labs
Respond to emergencies sensibly
 Inform a teacher if someone requires assistance
 If chemicals are spilled on skin, rinse with water for 20
minutes
 If you break something or spill something, please inform
a teacher immediately. Do NOT handle broken glass!
 If a fire starts, inform a staff member immediately –
STOP… DROP… ROLL!!!
IF YOU ARE NOT
SURE ABOUT
SOMETHING…
ASK A
TEACHER!!!!
V. Classifying Matter
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Matter is anything that has mass and
occupies space
Matter can be classified into two main
categories: Heterogenous &
Homogenous
Matter
Heterogeneous
Homogeneous
(Non uniform mixture)
i.e. cookie dough
(uniform matter)
i.e. water
Homogeneous Mixture
/ Solution
i.e. NaCl
Pure Substances
i.e. Lead
(aq)
Compounds
i.e. NaCl(s)
Elements
i.e. O2(g)
* This chart found on page 36*
- An atom is the smallest particle of an element which still
has the characteristics of the element. (O2(g), Cl2(g), K(s))
- Compounds contain more than one type of atom combined
in a definite proportion. (NaCl(s), KBr(s), HCl(aq))
1) Gravel and Sand
2) Vinegar
3) Nitrogen
4) Salt
Elements
I. Classifying Elements
Metals
-Solids
@ SATP
Nonmetals
-solids,
liquids,
gases
-Gain electrons to
-Ductile
form negative
-Good conductors
ions
-Lose electrons
-Brittle
to form positive
-Poor conductors
ions
-Lack luster
-Shiny
Metalloids
-Have
characteristics
of metals &
nonmetals
-Located near
staircase
II. The Periodic Table

John Alexander Newlands
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Arranged elements in order of increasing
atomic masses
Noticed some properties recurring over and
over again – he called this the periodic law
Dmitri Mendeleev
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Published the periodic table
of elements
Very confident as he left spaces
empty – assumed those elements
were not yet discovered
- Mendeleev used the terms FAMILY and PERIOD
to describe the table’s organization.
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FAMILY/GROUP: elements in vertical columns
– have similar properties.
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Reactivity INCREASES from
top to bottom within groups
1 and 2
Reactivity DECREASES from top
to bottom in groups 17 & 18.
(Fluorine is the most reactive
non-metal)
PERIOD: elements in
horizontal rows
– these elements change
from metals to nonmetals.
Groups of Elements
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Alkali Metals:
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Group 1 metals
Soft, silver coloured metals
that react violently with H2O
to form basic solutions
Most reactive: cesium &
francium
 Alkaline Earths:
 Group 2A metals
Light, reactive metals that
form oxide coatings when
exposed to air
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Transition Metals:
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Elements in groups 3 to 12
Exhibit a wide range of
properties
 Metalloids:
Metals very close to
the “staircase” line
They have
properties of metals
and non-metals.
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Halogens:
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Group 17, non-metals,
highly reactive.
Fluorine is the most
reactive
 Noble Gases:
 Group 18
 Generally unreactive
(inert)
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Lanthanides: atomic numbers 58-71
Actinides: atomic numbers 90-103
III. Atomic Theories
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Dalton:
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all matter is composed of tiny indivisible particles
called atoms
atoms of the same element have identical
properties
atoms can be combined to form new substances
 Thompson:
Discovered the electron – a subatomic
particle with a negative charge.
 He proposed the atom was a positive
sphere with negative electrons
embedded in the sphere.
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Rutherford:
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Suggested the existence of the proton –
subatomic particles with positive charge
His “gold” experiment led to the discovery
of the proton
Proposed that all atoms have a positive
central region called the nucleus

Bohr:
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Electrons orbit the
positive nucleus in
certain orbitals –
electrons cannot exist
between orbitals
The higher the energy
level of an electron, the
further it is from the
nucleus
Energy
Level
Maximum
Number
of
electrons
(e-)
1
2
2
8
3
8
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Quantum Mechanics:
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Highly mathematical
There is a region around the nucleus in
which there is a high probability of finding
an electron – the motion of the electron is
unknown.
Currently accepted model
VI. Back to the Periodic Table…
What do these tell us?
- atomic number
- group number
- atomic mass
- period number
In each atom, the number of protons equals the
number of electrons.
 The number of neutrons can be found by
subtracting the atomic number from the atomic
mass
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V. Simple Ions
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Ions are charged atoms.
Metals lose electrons to become positively
charged.
Groups 1, 2, & 3 will lose electrons to become
similar to the nearest noble gas.
Non-metals will
gain electrons
to obtain a
net negative
charge
Ion Formation
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All atoms want to have a stable (full)
outer energy ring
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They want to be more like noble gases
To become stable the atoms will gain or
lose electrons (whichever is easiest) to
fill the outer energy level.
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When they lose electrons, they become
positively charged
When they gain electrons, they become
negatively charged
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When atoms lose or gain electrons, they become
IONS.
To name an ion, follow these rules:
1) If ion is non-metal, change the ending to “-ide”
- ex. Chlorine → Chloride
Bromine → Bromide
2) If ion is a metal, call it the same and add the
word “ion” after it.
- ex. Sodium → Sodium ion
Iron → Iron ion
How do you calculate the charge of an ion?
1)
2)
3)
4)
Find the noble gas that the element is
closest to on the periodic table (does
not have to be in the same period)
Calculate if it would be easier to gain
or lose electrons to get the same
number of electrons as the closest
noble gas.
Calculate how many electrons the
element would gain or lose. (When you
gain electron the ion becomes positive,
when you lose, the ion becomes
negative)
Record the charge as a superscript
following the element’s symbol.
O
Gain electrons
2 electrons
O2-
VI. Isotopes
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ISOTOPES are
elements that have
the same atomic
number but different
atomic masses.
The differences in
atomic masses are
due to the addition or
removal of neutrons.
Protons?
Neutrons?
Electrons?
Protons?
Neutrons?
Electrons?
Protons - 10
Neutrons - 10
Electrons - 10
Protons - 35
Neutrons - 45
Electrons - 36