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PASS Content Standard 1.1
Matter is made up of minute particles
called atoms, and atoms are composed
of even smaller components (i.e. protons
neutrons and electrons).
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Inertia - 7 min
Matter is anything
that has inertia.
The resistance of
an object to a
change in motion.
If an object is at rest,
a force is needed
to make it move.
If an object is moving,
a force is needed
to slow it.
Atoms are so small that,
even today, direct visual
inspection is all
but impossible.
Our model of the atom
changes as our
experimental ability
improves.
Greek philosopher
around the year 400 BC.
Proposed that matter could
not be divided into smaller
and smaller pieces forever.
Used the word atomos
to describe the smallest
possible piece of matter.
An English chemist who
proposed the first atomic
theory in 1803.
1. All elements are composed
of indivisible particles.
2. Atoms of the same element
are exactly alike.
3. Atoms of different elements
are different.
4. Compounds are formed by
joining two or more elements.
Only one of his points
was incorrect - which one?
1. All elements are composed
of indivisible particles.
2. Atoms of the same element
are exactly alike.
3. Atoms of different elements
are different.
4. Compounds are formed by
joining two or more elements.
1. All elements are composed
of indivisible particles.
2. Atoms of the same element
are exactly alike.
3. Atoms of different elements
are different.
4. Compounds are formed by
joining two or more elements.
The English scientist who
discovered electrons in 1897.
Sometimes called the
"plum pudding" model.
Thomson thought of an atom as being
composed of positively charged
material with the negatively charged
electrons scattered through it.
The British physicist who
discovered the nucleus in 1908.
Rutherford proposed an atom
that is mostly empty space.
There is a small, positive
nucleus with negative electrons
scattered around the outside edge.
The Danish scientist who proposed
the Planetary Model in 1913.
Electrons move in definite orbits
around the nucleus, like planets
moving around the Sun.
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Bohr Model - 5 min
Can you identify
the element
represented
here?
Neon
Since 1935, many
physicists have
contributed to the
development of
"Quantum Mechanics"
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Quantum mechanics - 3 min
Quarks were
"invented" by
Murray Gell-Mann
and George Zweig
at Caltech in 1964.
The idea of quarks was not
taken seriously at first.
But experiments in the 1970s
began to provide evidence
supporting their existence.
The quark model is the best
theory we have today to
describe the structure of
atoms and molecules.
Up
Down
Charm
Strange
Top
Bottom
2
+ /3
- 1/3
+ 2/3
- 1/3
+ 2/3
1
- /3
Quarks are so small that
they could probably travel
through a mile and a half
of lead without hitting
another particle.
Quarks cannot exist
by themselves.
Quarks must be bound to
other quarks by the
exchange of gluons.
"Lightweight" particles
not composed of quarks.
Electrons are leptons
with a mass of
-31
9.1 X 10 kilograms.
"Heavy" particles
composed of 3 quarks.
Protons are baryons composed
of 2 Up quarks and 1 Down quark.
Protons have a mass of
-27
1.67 X 10 kilograms.
"Heavy" particles
composed of 3 quarks.
Neutrons are baryons composed
of 2 Down quarks and 1 Up quark.
Neutrons have a mass of
-27
1.67 X 10 kilograms.
Bosons are "force" carriers.
It is the exchange of these
particles between fundamental
particles that allows the formation
of more massive particles.
Photon - electromagnetic force
Gluon - strong nuclear force
+
o
W , W , and Z - weak nuclear force
Graviton - gravity
The graviton is the only force-carrying
particle that has not been observed,
either directly or indirectly.
Antiparticles have exactly the
same mass but opposite charges.
Leptons and quarks have anti-particles.
Bosons do not have anti-particles.
Today's atomic model explains
the structure of atoms using:
6 types of quarks
6 types of leptons
4 types of force carriers
Basic Subatomic Particles
Electrons have a
negative charge
and are found in
energy levels
outside the
nucleus.
Protons have a
positive charge
and are found in
the nucleus.
Neutrons do not have a charge
and are found in the nucleus.
Basic Subatomic Particles
The number of electrons
and protons in a
normal atom is
equal, giving
the atom an
overall neutral
charge.
All the atoms of
an element have
the same number
of protons,
indicated by the
atomic number
on the periodic
table.
Most elements have "isotopes", atoms
with different numbers of neutrons
Basic Subatomic Particles
An atom's valence
electrons (outer
energy level) are
easily changed
during chemical
reactions.
Atoms that have
gained or lost
valence electrons
are called "ions".
Protons and neutrons in the nucleus are
never changed during chemical reactions.
End
Content
Standard 1.1
Review
Physical Science
Content
Standard 1.1
1. What is science?
2. What is truth?
3. What are the
steps of the
scientific method,
beginning with the
first step?
4. What is a
hypothesis?
5. What is the
purpose of
an experiment?
6. What is chemistry?
7. What is physics?
8. What is matter?
9. What is inertia?
10. What is needed
to make an object
at rest begin to
move?
11. What is
Democritus
known for?
12. Who proposed
the first atomic
theory?
13. How many points
did Dalton's
theory have?
14. What is J.J.
Thomson
known for?
15. Who discovered
the nucleus of
atoms?
16. What do we
commonly call
Bohr's model
of an atom?
17. Who discovered
the neutron?
18. What subatomic
particles did
Gell-Mann and
Zweig "invent"?
19. What are the 6
flavors of quarks?
20. What is a lepton?
21. What is the mass
of an electron?
22. What is a boson?
23. What is the mass
of a proton?
24. What is a baryon?
25. What do we call
an atom with
a charge?
26. What are
isotopes?
27. Where are
valence electrons
found?
28. An atom has 9
protons and an
atomic mass of 19.
How many neutrons
does it have?
29. What are
antiparticles?
30. Which type of
boson has
never been
observed?
Tomorrow's test
will have 20 fill in the
blank questions.