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Chapter 3
Atoms, Elements, and the
Periodic Table
Important Vocabulary
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Matter
Atom
Law of Conservation of
Matter
Electron
Nucleus
Proton
Neutron
Element
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Atomic Number
Isotope
Mass Number
Atomic Mass
Metal
Non-Metal
Metalloid
Substance
Compound
Mixture
Launch Lab
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Get into your Science Teams
Look at the materials provided as I give
you directions
Question: Will you see all three states of
matter in this lab activity
Write your hypothesis
Perform the Experiment
Launch Lab Discussion
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What happened to the paper towel?
What caused this result?
Conclusion:
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Water was the liquid state of matter
The paper towel was a solid
The air in the cup was the gas
Air is matter because it occupies space
What is matter?
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Look at figure 1 on page 72. What in
these pictures is matter?
Matter is anything that has mass and
takes up space
Name some things that are not made up
of matter.
Atoms
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A small particle that makes up most matter
In your science journal, draw what you think
and atom looks like
At one time was believed to be a solid unit
Now broken into even smaller particles
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Neutron, electron, and proton
Democritus
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Greek philosopher, lived
from 460BC to 370 BC
Claimed that each type of
matter was made up of
specific atoms
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For example: solid water
(ice) is made of different
atoms than liquid water
His ideas were ignored
until the early 1800s
Lavoisier’s Contribution
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French chemist, lived 2000 years after
Democritus
Law of Conservation of Matter- Matter is
neither created nor destroyed. It simply
changes form
When you burn wood, what happens to
the log?
John Dalton
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Stated that matter is made up of atoms
that are too small to be seen
Claimed that each element was made up
of specific atoms that were unique to
that element
His findings are known as the atomic
theory of matter
JJ Thomson
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Observed that electricity flowed from negative
to positive components of a sealed tube and
could be bent by a magnet
He knew that opposites attract and the beam
was traveling towards a positive charge, so
therefore the beam must be made of negatively
charged particles
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Electrons- subatomic particles with a negative charge
So what keeps us from being
electrocuted?
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You don’t get a shock when you touch
everything, so what must also be present
in the atom?
A positively charged particle
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The proton
Ernest Rutherford
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In 1910, his team shot gold foil with alpha
particles
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Positively charged particles
Since all of the alpha particles did not pass
through the foil, he predicted that most of the
atom was made up of empty space
Rutherford’s results provided him with
information to name the nucleus
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Nucleus- Positively charged central part of the atom
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Contains protons
James Chadwick
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Assistant to Rutherford
Discovered the neutron- neutral particle
in the nucleus
Found this data when he noticed that the
gold atoms in the foil had released some
mass with no charge
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That unknown mass is what Chadwick called
the neutron
Modern Atomic Model
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Look at Figure 8 on pg. 78
This model is the accepted atomic model
(Bohr’s Model)
Notice the negatively charged electron
cloud and the positively charged nucleus
New Research
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Modern science has advanced atomic research
Protons and electrons have whole charges +1 or
-1
The particles in the nucleus are now broken
down into even smaller particles called quarks
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These particles are identified by their spin pattern and
have a fractional charge
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Up, down, strange, charmed, top, and bottom
The Simplest Matter
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Element- matter made up of only one
kind of atom
At least 115 elements are known and 90
of them occur naturally on Earth
Non-natural elements are known as
synthetic elements
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Formed from nuclear reactions in machines
known as particle accelerators
Organizing the Elements
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Dmitri Mendeleev organized the first
periodic table in order of each element’s
mass
His table only included 60 known
elements
The modern Periodic Table is organized
by atomic number
The Periodic Table
Structure and Organization of
Important Vocabulary
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Matter
Atom
Law of Conservation of
Matter
Electron
Nucleus
Proton
Neutron
Element
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Atomic Number
Isotope
Mass Number
Atomic Mass
Metal
Non-Metal
Metalloid
Substance
Compound
Mixture
What is an Atom?
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An atom is the simplest form of matter
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It is made of three major particles
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The Proton –
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The Electron –
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Positive Charge, In the Nucleus
Negative Charge, In the Shells and Orbitals
The Neutron 
No Charge, In the Nucleus
Let’s Draw an Atom
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+
+
+
-
Notice a few things about our
atom…
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How many protons does it have?
How many neutrons does it have?
How many electrons does it have?
What is the object in the center?
How many rings does it have?
How many electrons are on the outside
ring?
What do protons mean?
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The number of protons is also the atomic
number of the atom/element
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Example: Hydrogen, atomic symbol H, has 1
proton since it is element #1
How many protons does each of these have?
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Beryllium, Oxygen, Nitrogen, Xenon, Carbon
Name the element with the number of
protons shown.
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14, 27, 5, 30
What do Neutrons mean?
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If you add the number of neutrons and
protons, you get the atomic mass
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This is the decimal number underneath the
atomic symbol
Example:
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Magnesium is element #12
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How many protons?
Its atomic mass is 24.3050, which rounds to 24.
How many neutrons does Magnesium have?
What do electrons mean?
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Electrons are the negatively charged
particles located in the rings around the
nucleus
There are exactly the same number of
protons as there are neutrons
How many electrons:
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Sodium – Atomic Number 11
Silicon – Atomic Number 14
Arsenic – Atomic Number 33
What is the thing in the
center?
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That is the nucleus
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Review:
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What two particles are in the nucleus?
What overall charge does the nucleus have?
What do the rings mean?
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The number of rings tells you on which
row the element is located
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Hydrogen has how many rings?
How many rings does Helium have?
What about Carbon?
What about Iodine?
What do the outer electrons
mean?
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The outer ring electrons are called
valence electrons
These tell you to which column or family
the element belongs
Special Note: This only applies to families
1,2 and 13-18
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How many valence electrons does Hydrogen
have? Neon? Aluminum?
Now for Rules on Rings…
Ring Rules
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The inner ring, #1, can only have 2 electrons
The second ring can have up to 8 electrons
The third ring can have up to 18 electrons
The fourth ring can have up to 32 electrons
All rings up to ring #7, the last ring, can have
up to 32 electrons
KEY VOCAB: Energy Level – the rings containing
electrons are actually called energy levels
1
1
2
3
4
5
6
7
8
2
3
Transition Metals DO NOT
Follow Rules
4 5 6 7
Transition Metals
Noble Gases
Halogens
Alkaline Earth
Alkali
Naming the
Elemental Families
Organization on the Periodic
Table
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Rows are called families
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Have the same number of energy levels
Columns are called groups
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Have the same number of valence electrons
and bond similarly
Isotopes
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What do you know about isotopes?
Atoms with the same number of protons,
but different numbers of neutrons
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Isotopes determined by mass number (the
sum of protons and neutrons in the nucleus)
Mass number on the periodic table is the
average mass of the element
Hydrogen Isotopes
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Hydrogen has three
isotopes
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Protium
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1 proton, 0 neutrons
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Deuterium
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1 proton, 1 neutron
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Most abundant
radioactive
Tritium
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1 proton, 2 neutrons
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radioactive
Element categories
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Metals- shiny, metallic luster, good conductors of
electricity and heat
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Non-metals- usually dull in appearance, brittle (can
change shape)– be familiar with figure 17
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All metals are solid at room temperature except mercury
(liquid)
Usually poor conductors of electricity
Many are gasses at room temp
Metalloids- characteristics of metals and nonmetals, found
in a stairstep pattern between metals and non-metals
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All are solid at room temp
Metalloid Stairstep
Compounds and Mixtures
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Substance- mixture with the same
chemical properties throughout
Compound- substance whose smallest
unit is made up of atoms of two or more
elements
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Have properties different than the elements
that make up the compound
Compound Example
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What are some properties of hydrogen?
What are some properties of oxygen?
What are some properties of the
compound made up of 2 hydrogen atoms
and 1 oxygen atom?
What about 2 hydrogen and 2 oxygen?
Compounds
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Have formulas
Naming the formulas
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Prefixes: mono-, di-, tri-, quad-, pent- hex-,
hepto-, octo-, nono- decaSuffixes: -ine, -ane, -ite, -ate, -ous
Let’s practice a few naming problems
Name these:
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Sodium (Na) + Chlorine (Cl) = NaCl
Hydrogen (H) + Oxygen (O) = H2O
Hydrogen (H) + Chlorine (Cl) = HCl
Carbon (C) + Oxygen (O) = CO2
8 Hydrogen (H) + 3 Carbon (C) = H8C3
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Hydrocarbons have special naming techniqueswe will discuss these techniques in Chapter 9
Mixtures
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When two substances (elements or
compounds) do not combine to make a
new substance when mixed
What happens when you combine oil and
water?
Observe the bottle I have prepared.
Two kinds of Mixtures
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Homogeneous- the same throughout
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Examples: Teas, Soda, Fruit flavored soft
drinks
Heterogeneous- larger components that
are visibly different from one another
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Examples: Salads, cookies, mixed nuts
A Quick Review
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Describe and name the parts of an atom
Name 5 things that are matter and five
things that are not matter
What is the difference between atomic
mass and atomic number?
Name and describe the Isotopes of
Hydrogen
A quick Review
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What is an isotope and what makes them
possible?
Solve: An atom of Phosphorous has 15
protons and 15 neutrons, what is the
mass number?
Solve: The element Tungsten has a mass
number of 184, how many neutrons does
Tungsten have?
A Quick Review
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What is the difference between
homogeneous and heterogeneous
mixtures?
What three types of elements are there
and give properties of those elements?