Science 10
UNIT 1: ENERGY AND MATTER IN CHEMICAL CHANGE
Chapter 1: Atoms, Elements, and
Compounds
1.1 INVESTIGATING AND WORKING WITH CHEMICALS

Modern Chemistry has
a recent history
dating back to the
late 1700s. However,
chemical properties
and uses have been
known to different
civilizations for
thousands of years:
bluffton.edu
North American Aboriginal Peoples

Tanning leathers

Herbal medicines
chinesemedicineadvisor.com
uwlax.edu
Ancient Egypt
 Embalming
and
mummification
minnesota.publicradio.org
Ancient Rome, Greece, Persia
 Metal
 Dyes
working for armour
for art and paint
vector-clip-art.com
en.wikipedia.org
archive.worldhistoria.com
Material Data Safety Sheets (MSDS)

Even natural chemicals
must be handled properly
to ensure safety. Each
chemical today has a
Material Safety Data
Sheet (MSDS) to inform
you of its physical
properties (melting point,
boiling point, odour) and
hazards and instructions
for handling and storing it
safely.
Workplace Hazardous Materials
Information System (WHMIS)
WHMIS identifies eight classes of hazards:

Hazardous Materials are
covered by the Workplace
Hazardous Materials
Information System (WHMIS)
which informs workers about
the chemicals they work with in
three ways:
1.
Controlled products must have
informative labels in both English
and French on their containers
2.
Each controlled product must have
an MSDS
3.
Workers must complete an
education program that the
employer provides
Classifying Matter
Matter
- Anything with mass and volume
- May be solid, liquid or gas
Mixture
Pure Substance
- Combinations of
matter that can
be separated by
physical means
- Do not have
definite
composition
Heterogeneous Mixture
(Mechanical Mixture)
- Different components of the mixture
are visible
- Composition is variable throughout
the mixture
- Matter that has a
definite composition
Homogeneous
Mixture (Solution)
- Different components
are not visible
- Composition is
constant throughout
the mixture
Element
- Cannot be chemically
broken down into simpler
substances
Compound
-
-
Two or more
elements that are
chemically
combined
Can be separated
chemically into
simpler substances
Practice Problems pg. 10 #1-4
Chapter 1: Atoms, Elements, and
Compounds
1.2 DEVELOPING ATOMIC THEORIES
From Ancient Greece to today…
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Assignment

Create a chart that follows the development of the Atomic Model
throughout history. You can use the chart below to get started:
Model of the
Atom
Democritus
John Dalton’s
Billiard Ball
J.J. Thomson’s
Raisin Bun or
Plum-Pudding
Ernest
Rutherford’s
Model
Niels Bohr’s
Model
Why Model was
Proposed
Key Points of the
Model
Why Model was
rejected or
modified
John Dalton’s Atom
The Billiard Ball Model
1.
All matter is made up of small
particles called atoms
2.
Atoms cannot be created,
destroyed, or divided into smaller
particles
3.
All atoms of the same element are
identical in mass and size but
different in mass and size to atoms of
other elements
4.
Compounds are formed when atoms
of different elements combine in
fixed or definite proportions
5.
Chemical reactions change the way
atoms are grouped but the atoms do
not change
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The Cathode Ray Tube (CRT)
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
A gas discharge tube contains gas
at a low pressure.

When electricity is run through it, a
ray is formed and light is produced
across the tube.
J.J. Thomson (1856-1950)

J.J. Thomson determined that the
‘ray’ in the Cathode Ray Tube was
made up of a stream of negatively
charged particles

He added charged plates to
bend the cathode rays.

Based on the radius of the path,
he determined that the mass of
the particle was much less than
that of an atom and that the
negatively charged particle was a
unique particle – the electron.
cnx.org
The Raisin-Bun or Plum-Pudding Model
www.nobelprize.org

Since these negatively charged
electrons appeared to be present
in all samples of matter, Thomson
proposed that every atom
contained electrons.

Since most matter was neutrally
charged, there must also be a
positively charged part of the
atom.

Thomson thus proposed a
positively charged sphere with
many negatively charged
electrons present on the surface of
the sphere.
Ernest Rutherford (1871-1937)

Rutherford conducted his gold foil
experiment to further examine the
structure of atoms

He directed strongly positive alpha
particles towards a thin layer of
gold foil.

Most of the particles passed
straight through, however some
were deflected and even
bounced back.
www.rsc.org
Protons and a Nucleus
www.iun.edu

Since most of the particles passed
straight through, Rutherford
concluded most of the atom is
empty space

Since some of the particles
reflected and deflected there
must be a dense, massive nucleus
to each atom. He determined that
this was positively charged, made
up of protons

The negatively charged electrons
must orbit around the positively
charged nucleus much like
planets orbit the sun.
The Discovery of the Neutron
en.wikipedia.org

The Hydrogen atom is made up of
1 proton and 1 electron

Rutherford hypothesized that the
next biggest atom, helium, would
be 2 protons and 2 electrons.
Therefore it should have a mass
that is twice that of hydrogen.

Helium is 4 times more massive
than hydrogen.

The neutron was discovered as a
neutrally charged particle in the
nucleus that has the same mass as
a proton
Niels Bohr (1885-1962)

According to physical theory, the
electrons orbiting the nucleus, should
be losing energy in the form of light or
radio waves. Losing energy would
mean that the electron would come
out of orbit and crash into the nucleus.
This does not happen.

When electrical energy is applied to
gases, they do emit light – a specific
colour of light for each gas. Each
colour corresponds to a specific
wavelength of light or a specific
energy. Rutherford’s model did not
explain this, but Bohr’s did.
en.wikipedia.org
Energy Levels
library.thinkquest.org

Electrons in an atom have certain
allowed energies that enable the
atom to remain stable – energy
levels.

Electrons can only move from one
of these allowed energy levels to
another – they cannot exist
between them.

In order to jump from one level to
the next they will absorb a specific
amount of energy (jumping up a
level), or emit a specific amount of
energy (falling back down a level)
Our Working Model of the Atom…

Nucleons (protons and neutrons) make up the nucleus of an atom and
electrons fill the space around the nucleus.
Subatomic
Particle
Relative
Charge
Symbol
Mass (in g)
Radius (in m)
proton
1+
p+
1.67 x 10-24
10-15
neutron
0
n0
1.67 x 10-24
10-15
electron
1-
e-
9.02 x 10-28
Smaller than
10-18
Nuclear Notation

Isotopes – atoms made up of the
same number of protons, but
different number of neutrons

The atomic number is the number
of protons and identifies the atom

The mass number is the total
number of protons and neutrons

An atom has a neutral charge so
there are equal numbers of
protons and electrons in every
atom

Ex.
1 H
1
- mass number is top, atomic
number is bottom
There is one proton, zero neutrons,
and one electron.
The name is hydrogen - 1
Homework: pg. 23 #5-8, pg.24 #2, 4
Chapter 2: Names, Formulas, and
Properties
2.1 CHEMICAL NAMES AND FORMULAS
International Union of Pure and
Applied Chemistry (IUPAC)

Founded in 1919, IUPAC developed a systematic method to name
chemicals according to their composition.

The systematic name allows us to determine the chemical formula
and predict some of its properties.
Binary Compounds

Compounds that are made up of
two elements are called binary
compounds.

The names of binary compounds
almost always end with the suffix
“-ide”.
commons.wikimedia.org
Binary Molecular Compounds
montessorimuddle.org

A binary molecular compound
forms when two non-metallic
elements come together and form
a covalent bond (sharing
electrons).

Example – dihydrogen monoxide –
fatal if inhaled
Rules for Naming Binary Molecular
Compounds

1. The first element in the name
and formula is usually the one that
is furthest to the left on the
periodic table.

2. The suffix “-ide” is attached to
the name of the second element.

3. Prefixes are used to indicate
how many atoms of each type are
present in one molecule of the
compound.
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Examples:

NO

N2O

NO2

N2O3

N2O4

N2O5

Practice Problems pg. 44 #1-4
Names and Formulas for Binary
Ionic Compounds

A binary ionic compound is
composed of ions of one metal
element and ions of one nonmetal element joined by ionic
bonds.
elmhurst.edu
Rules for writing names and
formulas:
en.wikipedia.org

Ex. An ionic compound is made
between calcium and fluorine.

The name is calcium fluoride

The formula is CaF2
1.
The first element in the name and
formula is the metal.
2.
The second element is the nonmetal. The suffix “-ide” is attached
to the name.
3.
The chemical formula shows the
simplest whole number ratio of
each type of ion in the
compound.
*The names of ionic compounds DO
NOT contain prefixes*
Example: Predict the formula of
Lithium Oxide
Solution:
1.
Identify the type of compound – metal & non-metal therefore ionic
2.
Determine the charges on the ions – Li1+ and O2-
3.
The compound must be electrically neutral. Therefore it will take
two lithium ions to balance with one oxide ion.
4.
The formula is Li2O
Practice Problems: pg. 45 #5-8
Cation Charges

Many of the transition metals
(elements in groups 3-12) are able
to form more than one type of
cation.

Ex. Nickel can form Ni2+ or Ni3+

Ex. Copper can form Cu+ and Cu2+

If you are given the formula of an
ionic compound you can
determine the charge on the
cation.
en.wikipedia.org
Example: Which copper cation,
Cu+ or Cu2+, is in CuCl2
Solution:
1.
Begin by writing out the two ions involved. Chloride is always a Cl1and the copper could be either Cu+ or Cu2+
2.
The compound must be electrically neutral. If there are two Cl1ions then the single copper must be a 2+ charge.
3.
Therefore the cation is Cu2+
Practice Problems: pg. 46 #9, 10
Naming Cations Using the Stock
System

When writing the name of an ionic
compound that consists of a
transition element that could be
different charges, the charge on
the cation is written in
parentheses, as a Roman numeral
after the name of the metal.

Example: Cu2+ is copper (II)
Example: Write the chemical
formula for copper(II) oxide
Solution:
1.
The copper cation is named copper(II) and therefore is Cu2+
2.
The oxide anion is always O2-
3.
The compound must be electrically neutral so the charges must
cancel.
4.
Therefore, one copper(II) ion will combine with one oxide ion.
5.
The formula is CuO
Practice Problems: pg. 47 #11-12
Homework: Investigation 2-A
Compounds Containing
Polyatomic Ions

Many ionic compounds are not
binary because they are made up
of one or both ions containing
more than one type of atoms –
polyatomic ions.

Polyatomic ions are made of
covalent bonds that as a group
have a collective positive or
negative charge.
www.fccj.us
Example: What is the formula of
ammonium sulfide?
Example: What is the name of
CuCO3
Practice Problems: pg. 52 #13-16
Families of Polyatomic Anions

Ex. Nitrate, nitrite or sulfate, sulfite

Patterns exist:
1.
In each family, the anion ending
with “-ate” serves as a reference
point. The other anions are named
according to the number of
oxygen atoms in their formula, in
relation to the reference anion.
2.
Compared with an “__-ate” anion,
an “___-ite” anion has one less
oxygen in its formula
4. Compared with an “____-ate”
anion, a “hypo___ite” has two less
oxygen atoms in its formulas
5. Compared with an “____-ate”
anion, a “per_____ate” has one more
oxygen atom in its formula.
Practice Problems: pg. 53 #17-19
Hydrogen Compounds

Hydrogen is a non-metal even
though it appears on the left side
of the periodic table.

Therefore, these hydrogen
compounds are molecular but
they do not use prefixes

Common examples are on Table
2.5 on pg. 54 in textbook.

Homework: pg. 55 #1-6
Chapter 2: Names, Formulas, and
Properties
2.2 EXPLAINING PROPERTIES OF SUBSTANCES
Bonding and Properties


One of the ways Chemists
determine features about the
structure and bonding of different
substances is to observe physical
and chemical properties such as:

Melting point

Boiling point

Electrical conductivity when
dissolved in water
Chemicals have different
properties in different states so we
use subscripts to show the state of
a substance – (s) , (l) , (g) , (aq)
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Properties of Ionic Compounds
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1.
In solid state, ionic compounds
have regular crystalline shapes
with flat sides.
2.
Ionic compounds tend to have
high melting points suggesting the
bonds between cations and
anions is very strong.
3.
In the solid state, ionic compounds
do not conduct electricity
suggesting ions are not free to
move.
4.
When melted or dissolved in
water, ionic compounds are
electrolytes – they conduct
electricity.
Properties of Molecular
Compounds
1.
Most molecular compounds have
relatively low melting points
suggesting that the attractive
forces between molecules must
be weak.
2.
Once melted, molecular
compounds can be heated
further without decomposing
suggesting the covalent bonds
within molecules are strong.
3.
Molecular substances are nonelectrolytes or they do not
conduct electricity in any pure
state.
4.
Some molecular compounds do
conduct electricity when dissolved
in water
en.wikipedia.org
Toxic Properties of Substances
www.virtualmedicalcentre.com

Every chemical has potential risks
that can be harmful.

Deciding to use chemicals always
involves balancing risks and
benefits based on what you know
about their properties.

Table 2.8 on pg. 60
Check Your Understanding:

Pg. 62 #1-5
Chapter Two Project

Investigation 2-C Reducing the
Risk

Pg. 61
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