Post on 23-Mar-2018
GRADE 9 SCIENCE
UNIT 1: ATOMS, ELEMENTS, AND
COMPOUNDS C H A P T E R 1
UNIT TERMS
Use term handout to define all terms for this unit.
1.1 SAFETY IN THE SCIENCE CLASSROOM
Read pages 8-9
Activity 1-1A – Page 9
** Look for 14 things!
Page 10-11
WHIMIS SYMBOLS
Page 12
ExploreMore - Page 13
http://www.sciencelab.com/msds.php?msdsId=9927209
1.2 INVESTIGATING MATTER
WHAT IS MATTER?
Matter is anything that has mass and volume.
Mass is the amount of matter in a substance or object.
Volume is the amount of space a substance or object occupies.
Matter is made up of elements
• Elements are substances that contain one type of matter and
cannot be broken down or separated into simpler substances
• In chemistry, the Periodic Table of Elements is used to organize
elements
PERIODIC TABLE OF ELEMENTS
DESCRIBING MATTER 1. Physical Properties (p. 18)
• Characteristics of matter that are often observed or measured
• Can be either qualitative (observed) or quantitative (measured).
EXAMPLES OF PHYSICAL PROPERTIES
Color
Malleability
Luster
Conductivity
Boiling Point
Melting Point
Texture
Magnetism
Density VIDEO
DESCRIBING MATTER CONTINUED PG. 19
2. Chemical Properties
• Observed when substances react with each other
• Determines a substances usefulness
• Examples
Reactivity
Combustibility
Toxicity
CORE LAB
Physical & Chemical Properties
Page 20
SECTION 1.3 ~ ATOMIC THEORY
THEORY VS. LAW
• A theory is less well supported
than a law.
• Most laws are supported by
different and robust experimental
evidence.
ATOMIC THEORY • The descriptions of matter and how it
behaves.
• Has undergone many modifications as
new facts became available.
EARLY IDEAS….2000 YEARS AGO
Empedocles: matter was
composed of four “elements:”
Earth
Air
Wind
Fire
Aristotle agreed with Empedocles and no one
seriously challenged it for the next 2000 years.
Democritus: eventually a
substance will be cut into a piece
that can no longer be cut. He
called this piece atomos.
THE DEVELOPMENT OF THE ATOMIC THEORY
• John Dalton (1766-1844)
• British schoolteacher and scholar
• He is credited with developing a theory that
was a new way of describing matter
• He suggested that the particles that make up
matter are like small, hard spheres that are
different from different elements
• He defined an atom as the smallest particle of
an element
DALTON’S ATOMIC THEORY
• All matter is made up of small particles called
atoms
• Atoms cannot be created, destroyed, or
divided into smaller particles.
• All atoms of the same element are identical in
mass and size, but they are different in mass
and size from the atoms of other elements
• Compounds are created when atoms of
different elements link together in definite
proportions.
DALTON’S MODEL…BILLIARD BALL MODEL
J.J. THOMSON
• British physicist
• He studied electric currents in gas discharge tubes,
which are related to today’s fluorescent lights.
• He suggested that all atoms must contain electrons
(negative charge)
• His model pictured a positively charged ball with the
negatively charged electrons embedded in it.
THOMSON’S MODEL…RAISIN BUN MODEL
• Pictured positively
charged ball like a
bun with negatively
charged particles
embedded in it like
raisins
ERNST RUTHERFORD (1871-1937)
• He was a scientist from New Zealand (worked at McGill University, Montreal)
• He discovered that atoms have a nucleus
• Nucleus: the tiny, dense, positively charged centre of the atom
• There are two kinds of particles in the nucleus; protons (positive charge) and neutrons (neutral)
RUTHERFORD’S MODEL…
PLANETARY MODEL
NIELS BOHR (1885-1962)
• He proposed that electrons
surround the nucleus in specific
energy levels or shells.
• Each electron has a particular
amount of energy.
BOHR’S MODEL…ORBITAL MODEL
• Rutherford was able to develop Thomson’s model due to the development of new technologies (gold foil experiment)
• The development of cyclotrons and proton accelerators have further developed the model accepted today.
SUMMARY
DEVELOPMENT OF ATOMIC THEORY
WORKSHEET
ATOMIC THEORY DEVELOPMENT RECAP
- CUE CARDS + MARKER
Who described matter as being made up of four
elements; earth, air, wind and fire?
a) Aristotle
b) Democritus
c) Empedocles
d) JJ Thompson
Who agreed with Empedocles theory about
the four elements:
a)Aristotle
b)Democritus
c)Empedocles
d)JJ Thompson
Who described a substance that could no longer
be cut as an atomos?
a) Aristotle
b) Democritus
c) Empedocles
d) JJ Thompson
Who defined the atom as the smallest
particle of an element?
a)Aristotle
b)Democritus
c)JJ Thompson
d) John Dalton
Who said that all matter is made up of
particles called atoms?
a)Aristotle
b)Democritus
c)JJ Thompson
d) John Dalton
Who stated that atoms cannot be created, destroyed or divided into smaller
particles?
a)Aristotle
b)Democritus
c)JJ Thompson
d) John Dalton
What are electrons?
a)Neutrally charged particles
b)Negatively charged particles
c)Particles with no charge
d)Positively charged particles
What are protons?
a)Neutrally charged particles
b)Negatively charged particles
c)Particles with no charge
d)Positively charged particles
What are neutrons?
a)Neutrally charged particles
b)Negatively charged particles
c)Particles with no charge
d)Positively charged particles
Who suggested that all atoms must contain
electrons?
a) Aristotle
b) Democritus
c) Empedocles
d) JJ Thompson
Whose theory does this diagram represent?
a) Aristotle
b) Democritus
c) Empedocles
d) JJ Thompson
Who discovered that atoms had a nucleus?
a) Aristotle
b) Democritus
c) Ernest Rutherford
d) JJ Thompson
Which best describes the nucleus of an atom?
a) Tiny, dense and positively charged
b) Tiny, dense and negatively charged
c) Large, dense and positively charged
d) Large, dense and negatively charged
What are the two types of particles in
the nucleus?
a)Neutrons and protons
b)Neutrons and electrons
c)Protons and electrons
d)None
Who proposed that electrons have a
particular amount of energy and
surround the nucleus?
a) Aristotle
b) Democritus
c) Ernest Rutherford
d) Neil Bohr
INSIDE THE ATOM
• An atom is the smallest particle of an element that
retains the properties of the element.
• All atoms are made up of three kinds of smaller
particles call subatomic particles.
• Three Subatomic Particles:
Protons (positively charged)
Electrons (negatively charged)
Neutrons (no charge)
Subatomic
Particle
Charge Mass Location
Proton (p+) + Large Nucleus
Neutron (n) 0 Large Nucleus
Electron (e-) - Very small Energy
Levels
THE ATOM
MASS
• Protons and neutrons have much more mass than electrons
• This means that when you lift up a large rock, it is the protons and neutrons in the rock that weigh it down
• Protons and neutrons have about the same mass…but they have about 1800 times more mass than an electron
ELECTRIC CHARGE
• The electric charge comes in two types:
Positive
Negative
• Because negative and positive charges attract each
other, protons (positive) and electrons (negative) are
attracted together
• Each proton counts as +1, and each electron counts -
1.
• All atoms have an equal number of protons and
electrons
• This means that the charges add up to zero, making
the atom uncharged or neutral.
READ PAGES 28 - 29
Test your knowledge:
http://www.chem4kids.com/files/atom_structure.html
QUESTIONS PAGE 33
#15, 17