TAKS objective 3 Structure and Properties of Matter

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TAKS objective 3Structure and Properties of
Matter

• Middle School Science
• Science TAKS Need to Know

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Atomic Theory

• Atoms are building blocks of elements
• Atoms in each unique element are the same.
  (Ex Every oxygen element has the same of
  protons)
• Atoms are different from atoms of other elements
  (Ex Hydrogen has a different of protons than
  oxygen)
• Two or more different atoms bond in simple ratios
  to form compounds (Ex Hydrogen oxygen can
  chemically combine to form water- H2O )

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solid
liquid
gas
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Atoms and Elements
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Atomic Particle Charges

• Protons Positive
• Neutrons Neutral
• Electrons Negative -

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Location of Subatomic Particles

• 10-13 cm
• electrons
• protons
• neutrons
• 10-8 cm

nucleus
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Location of Atomic Particles

• Inside the Nucleus
• Protons with a Positive charge
• AND
• Neutrons with a Neutral charge that means they
  do not have a charge

• Outside the Nucleus- in electron cloud
• Electrons with a Negative charge
• Did you know electrons are very, very small and
  move very, very fast???

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Periodic Squares
11 Na 22.99

• The periodic square for an element
  can tell you lots of information
  about that atom.
• Atomic number of protons
• Atomic number of electrons
• That means in a neutral (uncharged) atom the of
  protons and electrons are always the SAME!!!!

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Atomic Mass on the Periodic Table

• 11
• Na
• 22.99

Atomic Number or Protons
Symbol
Atomic Mass or Protons neutrons
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Atomic number

• Atomic number
• of Protons

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Mass Number

• The number
• of
• protons and neutrons
• in an atom

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Number of Electrons

• A balanced atom is neutral
• The net overall charge is zero
• Number of protons Number of electrons
• Atomic number Number of electrons

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Elements with similar properties are placed in
the same group in the periodic table. The
stair-step line separates the elements into
metals and nonmetals.
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Metals Nonmetals
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26
30
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Ru and Os
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12
12
Ca and Sr
126
82
82
Sn and Ge
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7
7
P and As
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Specific Heat
Measure of how much heat matter can absorb. It
is a measure of how much heat energy it takes to
make 1 gram of a substance rise 1o C in
temperature. Heat is measured in calories. A
calorie is the amount of heat needed to make 1 g
of water rise 1o C in temperature.
The higher a substances specific heat, the
harder it is to increase its temperature (as with
the cloth car seat). The opposite is also
true a substance with lower specific heat
increases in temperature very easily (as with the
metal car door).
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If you want to keep the temperature of something
from changing very muchbuild it out of a
material that has a high specific heat.
Most metals have low specific heats, while
nonmetal compounds mixtures such as water,
wood, soil, air have relatively high specific
heats.
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How the specific heat of water affects the Earth
Oceans cover about 2/3 of Earths surface.
Waters characteristic of retaining heat is
important to our climate. It means that our
climate stays much more stable than it would if
there were less water on Earth.
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Molecules Compounds
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Pure substances
Compounds
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Mixtures
Combination of two or more pure substances.
Substances are mixed together but have not
reacted to form any new molecules.
Example- Sugar (a compound) dissolves in water
(a compound) to form a mixture. The molecules of
sugar and water do not change chemically. They
just become mixed together.
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Properties of matter
Physical properties can be observed without
changing the substance into a different
substance.
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Chemical Properties
Characteristics of a substance that are observed
when it reacts (changes) to produce one or more
different substances. Example- Water can be
changed into hydrogen gas and oxygen gas using an
electric current. When water molecules change
chemically into hydrogen gas and oxygen gas, we
say that a chemical change has occurred.
Hydrogen gas and oxygen gas each have a different
set of properties. Substances change into
different substances through chemical reactions.
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Chemical Reactions
Substances change into other substances in
chemical reactions. The atoms in the original
substance are rearranged. The bonds in the
original substance may be broken and new bonds
may be formed between different atoms. This
produces one or more new substances that may be
either pure elements or compounds. The products
of a chemical reaction always have difference
chemical and physical properties than the
original substance(s).
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Chemical Equations
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Balancing Equations