Science Question of the day!
 Would you weigh more or less on the moon than you
do on earth?
 Write the question and the answer in your science
notebook. Be sure to explain your reasoning and use
complete sentences!
Answer!
 The gravity on the moon is 1/6 of that of the earth;
therefore, a person will weigh 1/6 of their weight on
earth on the moon. That means I would weigh
approximately 19 lbs. How much would you weigh?
The unleashed power of the atom has changed everything save
our modes of thinking, and we thus drift toward unparalleled
catastrophe.
Albert Einstein
.
An Introduction to the Atom
What is an atom?
 Matter is made up of atoms.
 How many atoms do you suppose are in this one grain
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of salt?
There are more than 2,000,000,000,000,000,000 (2
quintillion) atoms.
Atoms were though to be the smallest units of matter,
and they cannot be divided.
Later, it was found that there are subatomic particles
that make up atoms.
What are these subatomic particles?
The Structure of Atoms
The Nucleus
 The nucleus is not a subatomic particle.
 It is, however, the home of subatomic particles in an atom.
 The nucleus is small, but it makes up almost 99% of the
mass of the atom.
 The nucleus is the center of the atom, and it contains a
positive electric charge.
Subatomic Particles: Protons
 A proton is a subatomic particle that has a positive
electrical charge.
 Each nucleus contains at least one proton.
 Protons are made of even smaller particles called quarks.
 There are over 100 subatomic particles, but we will only talk
about three: protons, neutrons, and Electrons.
Time for a “good” Proton joke
 A proton and a neutron are walking down the street.
The proton says, "Wait, I dropped an electron help me
look for it."
The neutron says "Are you sure?" The proton replies
"I'm positive.“
 HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA
HAHAHAHAHAHAHAHAHAHAHAHAHAHA!
 That was so funny.
Science Question of the day!
 Why do stars twinkle?
 Write the question and the answer in your science
notebook. Be sure to explain your reasoning and use
complete sentences!
Answer!
 Light reaches us after it is refracted through various
layers of air. As light passes through the earth’s
atmosphere, it is made to flicker by hot and cold
ripples of air. This is what makes it seem like it is
twinkling. It would be like looking at light through
heat waves off the road in the summer. The image is
somewhat distorted because of the movement of the
air.
Subatomic Particles: Neutrons
 A neutron is a subatomic particle that has the same
mass as a proton, but no electrical charge.
 Neutrons are also found in the nucleus with the
protons.
Subatomic Particles: Electrons
 An electron is a negatively charged subatomic
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particle.
They are constantly moving around the nucleus.
They are much smaller than neutrons and protons.
Electrons exist in a cloud around the nucleus.
This cloud makes up the borders of the atom.
Electron Behavior
Time for some practice…
 For homework tonight, you will read “What Are
Atoms” and complete questions 1-6 for homework.
 We will check this tomorrow! Remember, I care more
about effort than I do about having all the right
answers.
Science question of the day!
 Why aren’t birds electrocuted when they sit on power
lines?
 Write the question and the answer in your science
notebook. Be sure to explain your reasoning and use
complete sentences!
Answer!
 He isn’t a drumstick at KFC because the bird is only
touching one line. The bird would have to touch two
lines in order to create a complete circuit for the
electricity to travel through.
Atomic Number
 The number of protons in an atom is called the atomic
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number.
For example, any atom with only one proton is called a
hydrogen atom. Any atom with eight protons is called
an oxygen atom.
Why is this important?
The atomic number is important because it tells us
what family of elements the atom belongs to.
This will become more important in the next part of
the chapter.
Ions
 Ions are a special kind of atom that have either more or
fewer electrons than protons.
 This happens both in nature and in laboratories when
atoms undergo a large amount of radiation or are
subjected to mass amounts of energy all at once.
 Ions are necessary in our chemistry.
Isotopes
 Isotopes are atoms that have the same number of
protons, but a different number of neutrons.
 Neutrons help add to the mass of the atom, and if an
atom has more neutrons it will weigh slightly more
than an atom that has few.
Science question of the day!
 Why is the sky blue?
 Write the question and the answer in your science
notebook. Be sure to explain your reasoning and use
complete sentences!
Answer!
 Violet and blue light have short waves which are
scattered more than red light waves. While red light
goes almost straight through the atmosphere, blue and
violet light are scattered by particles in the
atmosphere. Thus, we see a blue sky.
Elements and Isotopes
What holds an atom together?
 You might initially think that gravity holds atoms together.
 Electrical charges hold the atom together. Opposites
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attract! Just like magnets.
Like magnets, like charges repel each other.
Let’s try it with magnets to see what’s going on in an atom.
But wait! There is a strong nuclear force at work here that is
holding the atom together. It overcomes the repulsion of
the charges.
Without it, our universe would collapse.
Ions
Since you are so interested in
nuclear reactions…
Elements of Matter
 What are the properties of elements?
 Today, we will do an experiment to try and classify elements.
 Perform the experiment on pages E12 and E13
 Use the chart to record your observations of each substance.
 Classify the materials into two separate groups: metals and
nonmetals.
 Answer questions 1-3 on page E13 on the back of the chart.
 Complete this for homework due tomorrow!
Science question of the day!
 How does sunscreen work?
 Write the question and the answer in your science
notebook. Be sure to explain your reasoning and use
complete sentences!
Answer!
 Sunscreen works by combining organic and inorganic
active ingredients. Inorganic ingredients like zinc
oxide or titanium oxide reflect or scatter ultraviolet
(UV) radiation. Organic ingredients like octyl
methoxycinnamate (OMC) or oxybenzone absorb UV
radiation, dissipating it as heat. Some sunscreens
protect us from the two types of damaging UV
radiation: UV-A and UV-B. Both UV-A and UV-B
cause sunburns and damaging effects such as skin
cancer.
The Elements of Matter
 What is an element?
 An element is a pure substance that’s made up of only
one kind of atom.
 Elements cannot be broken down into different
substances.
 There are 90 known elements that occur in nature,
and 22 have been created in a laboratory for a total of
112 elements.
 Did you know that all natural elements are born from
the death of a star?
How Elements are Formed
How elements are formed
 As you learned from the video, only hydrogen and
small traces of other elements existed at the beginning
of the universe.
 Through a process called fusion, subatomic particles
join to create new elements.
 Most elements exists in the solid state at room
temperature, but some exist as gases (oxygen, helium,
hydrogen, etc.), and some exist as liquids (mercury,
bromine).
Experiment Results: Metals vs.
Nonmetals
 75% of elements on earth are metals.
 You can determine metals from nonmetals using
specific properties. What properties do you think we
use?
 Fun Fact: One property we did not use in our
experiment was heat conduction. Metals are great
conductors of heat and electricity. That is why you
shouldn’t stand under an umbrella in a thunder storm.
Duh!
Time for a little practice…
 For homework tonight, read “What Are Elements”, and
complete questions 1-6 for homework.
 Remember, I care more about your effort than whether
or not your answers are correct!
Science question of the day!
 What are the northern lights?
 Write the question and the answer in your science
notebook. Be sure to explain your reasoning and use
complete sentences!
Answer!
The Periodic Table
 Let’s get the bad news out of the way first… You have a quiz over the
Periodic Table one week from today.
 But…
 We have a fun rap to help us…
 http://www.youtube.com/watch?v=lDp9hUf_SV8&feature=related
Periodic Table History
 The periodic table did not always look the way it does now.
 In 1869 Dmitri Mendeleev placed elements into a table
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based on their atomic masses.
He noticed their properties fell into repeating patterns, but
their were gaps in the patterns.
He hypothesized that the gaps should be filled with
elements that had yet to be discovered.
He was correct!
The table was later organized by atomic number rather
than mass.
How to read the table
 Each square represents an element.
 Each square contains the element’s atomic number,
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chemical symbol, name, and atomic mass.
The colors identify whether the element is a solid
liquid or gas at room temperature.
Open your books to pages E16 and E17.
What do the colors mean?
Color also identifies natural vs. man-made elements.
How to read an
element
-This is cobalt
-What is it’s
symbol?
-What is cobalt’s
atomic
weight/mass?
-What is it’s atomic
number?
-Pretend the color is
dark yellow. What
does it’s color tell
us?
Time for some “good” jokes
 Anyone know any jokes about sodium?
 Na
 Gold walks up to the basketball court and says , “Hey,
can I play?”
 Helium replies, “Au! Get our of here!”
 Making good chemistry jokes is hard because all the
good ones Argon.
 I crack myself up…
Families of Elements
 Families of elements usually have the same characteristics.
 Families are in columns.
 Column 1: metals that react strongly with other elements
 Column 2: metals that react less strongly but burn brightly
when heated
 Columns 3-14: common metals that do not react strongly at
all
 Columns 15-17 in a stair-step: nonmetals (react strongly
with metals from column 1)
 Column 18: Noble gases (hardly react at all)
Time for a little practice…
 For homework tonight, read “The Periodic Table”, and
complete questions 1-5.
 Remember, I care more about effort!
Changes of State
 Time for an experiment…
 Perform the experiment on pages
E20 and E21.
- Record the temperatures on the chart paper.
- Create a line graph showing the change in temperature
- Answer questions 1-3 on page E21.
- Complete the line graph and questions for homework tonight due
tomorrow!
Forms of Matter
 We have learned that elements are only made of one
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kind of atom.
However, atoms can join together to form molecules.
They can be atoms of different elements, such as the
molecular formulation for water: H2O
What do you think this formula means?
Molecules form when electrons in two or more atoms
are attracted to the nuclei of both atoms.
The atoms act and move as a single particle: a
molecule.
States of Matter
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Do you know what the states of matter are?
Solid- definite shape
Liquid- definite volume, but no definite shape
Gas- no definite or volume
Can you think of a molecule that can exist in all three
states?
 Did know there is one more state of matter?
 Plasma- composes nearly all the matter in the universe;
contains no electrons, so it is able to move freely; stars, like
our sun, are made of plasma! Lightning, neon signs, and
fluorescent light bulbs are also made from plasma.
A little more on the States of
Matter
Physical Science: States of Matter
Characteristics of Matter
 Solids- Molecules are held tightly together and do not
have freedom of movement. They do not move from
their fixed positions.
 Liquids- Molecules are not held in fixed positions.
They are close together, but they have freedom of
movement.
 Gases- Molecules are father apart and can drift away
from one another. Gases, unlike liquids and solids, can
be compressed easily.
Changes of State
 As the chalkboard picture indicated earlier, matter can
change it’s state of being when energy is applied.
 When energy is added (like heat) the molecules move
faster and faster.
 With enough energy, a solid can change to a liquid,
and a liquid can change to a gas.
 Let’s look at my example…
Changes in State
 The temperature at which matter changes varies based
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on the substance.
The temperature at which a substance changes from a
solid to a liquid is called its melting point.
The temperature at which a substance changes from a
liquid to a solid is called its freezing point.
The temperature at which a substance changes from a
liquid to a has is called its boiling point.
Pressure can also change state. For example, if a gas is
compressed enough it can change to a liquid.
Science question of the day!
 What causes the sound of thunder?
 Write the question and the answer in your science
notebook. Be sure to explain your reasoning and use
complete sentences!
Answer!
Chemical Compounds
 A compound is a substance formed of the atoms of two
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or more elements.
We talked about H2O earlier, this is a compound of
two hydrogen molecules and one oxygen molecule.
This is a chemical formula. The two means there are
two hydrogen molecules.
There is no number after the O because there is only
one oxygen molecule.
Compounds can also be made when a chemical
reaction takes place. Like rust on a nail, for example!
Time for a little practice…
 For homework tonight, read “What Are Compounds,
and answer questions 1-6.
 EFFORT!
Science question of the day!
 Why don’t I fall out of a roller coaster when it goes
upside down? Don’t say because of my seatbelt or
harness!
 Write the question and the answer in your science
notebook. Be sure to explain your reasoning and use
complete sentences!
Answer!
Acids and Bases
 Acids are compounds that react easily with other substances.
 Bases are compounds that also react easily with other substances.
 Acids and bases are on two opposite ends of a scale known as the
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pH scale.
The scale goes from 0-14, with acids falling between 0-7 and
bases falling between 7-14.
0 is the strongest acid, and 14 is the strongest base.
Water has a pH of 7. It is a neutral substance as are all substances
with a pH of 7.
All substances fall somewhere on the pH scale.
When mixed, equally strong acids and bases can neutralize one
another.
Uses of Acids and Bases
 We have hydrochloric acid in our stomachs to digest
food.
 Acids are used in fertilizers.
 Bases are used to create cement.
 Acids and bases are both used to develop pictures.
Identifying Acids and
Bases
 Time for an experiment…
 Complete the experiment on the
handout and complete the questions
that go along with the experiment.
- The results from your experiment will be due
tomorrow!