Module 4 Review
Module 4 Review
Module 4. 01 Atomic Theory Review
*Matter- is anything that has mass and takes up
space.
*Element- substances could not be divided into
other substances by any means.
*Atom-The smallest unit of an element
subatomic particles –is Protons, neutrons, and
electrons
*Proton- subatomic particle that has a positive
(+) charge. It has a mass number of 1 and is
always located in the nucleus.
Module 4. 01 Atomic Theory Review
*Neutron-is a subatomic particle meaning it has
no charge. It has a mass of number 1 and is always
located in the nucleus.
*Electron- is a subatomic particle with a negative
charge (-). It is much smaller than the proton and
neutron, and has a mass of number 0. The
electron is located cloud that surrounds the
nucleus.
*Nucleus- the center of the atom, there is a very
small region. The nucleus contains the protons
and neutron.
Module 4. 01 Atomic Theory Review
*Electron Cloud-the area around the
nucleus. This area makes up the majority of
the volume of the nucleus. This is also
mostly empty space and constantly
moving.
Examples of Matter
Review 4.02
Atomic Model-Dalton’s Theory
* All matter is made of atoms.
*Scientists still hold this to be true. All matter that has been studied
and observed seems to be made up of atoms.
*All atoms of a given element are the same.
*We now believe that atoms of the same element have the same
number of protons. However, you will learn in later lessons that
atoms of the same element may have different numbers of neutrons.
Atoms with the same number of protons and different number of
neutrons are called isotopes.
*Different elements are made up of different atoms.
*Scientists still hold this statement to be true. Atoms of different
elements have different numbers of protons. The number of protons
in an atom is used to identify the element.
Review 4.02
Atomic Model-Dalton’s Theory
* Atoms cannot be divided into smaller pieces.
*We now know that atoms are made up of
subatomic particles: protons, neutrons, and
electrons.
*Atoms of different elements combine in whole
number ratios to make compounds.
*As you will see in the next few lessons, atoms
bond together in whole number ratios to make an
almost unlimited amount of different
compounds.
4.02 Atomic Model Scientists
Thomson
*At the beginning of the 20th Century,
Thomson’s atomic model was accepted as
the correct representation of the atom. In
Thomson’s model, negatively charged
electrons were dispersed inside an area of
positive charge. The positive and negative
charges canceled out each other, resulting
in a neutral atom.
4.02 Atomic Model Scientists
Rutherford
*Ernest Rutherford
an English scientist, designed an experiment to
test Thomson’s atomic model. Rutherford
planned to fire heavy, positively charged, fast
particles on a very thin metal foil, made of gold.
A screen was placed around the gold foil. This foil
was sensitive to particles that were fired and
would show how the particles were affected by
the foil. This set up was like firing a heavy cannon
on a tissue paper. Rutherford did not expect the
particles to get effected at all.
4.02 Atomic Model Scientists
Bohr
*Bohr stated electrons used specific orbits
while moving around the nucleus. An
electron could jump to a higher orbit if it
gained energy or a lower orbit if it lost
energy. Bohr’s model meant laws of
classical physics did not apply to atoms.
Bohr’s model was the beginning of a new
field of study, called quantum physics.
4.02 Atomic Model Scientist
Review
*Thomson’s model, consisting of
negatively charged electrons inside an area
of positive charge, was accepted as the
correct representation at the beginning of
20th century.
4.02 Atomic Model Scientist
Review
*Rutherford proved the atom had a very
dense core by his gold foil experiment.
Investigating further, scientists discovered
that an atom consisted of a nucleus
containing protons and neutrons, and
electrons that orbit around that nucleus
4.02 Atomic Model Scientist
Review
*Latest models state it is not possible to
determine exact location of an electron.
Therefore, scientists define an electron
cloud as the location where an electron is
most likely to be found
4.03 Introduction to Periodic Table
In 1869, Dmitri Mendeleev, a Russian
chemist, set out to organize the known
elements according to their properties. He
noticed that when elements were arranged
by increasing mass, there were repeated or
periodic patterns in their properties.
*
4.03 Moseley
In 1911, the English scientist Henry
Moseley discovered something that helped
explain why some of the elements were out
of order by mass.
*
*Moseley discovered that the periodic
pattern was determined by the number of
protons in the element’s nucleus, not the
mass of the atoms.
4.03 Periodic Table
His discovery led to the definition of the
term atomic number . The atomic number
represents the number of protons in an
atom of a given element.
*
*Today, scientists still recognize that the
atomic number as the basis of the
organization of the periodic table.
4.03 Properties of Metals
*Properties
of Metals
*Metals are good conductors of heat and
electricity.
*They are also solids at room temperature.
*Metals are ductile. Ductility is the ability to be
drawn into wire.
*Metals are malleable. Malleability is the ability
to be rolled into thin sheets.
*Metals also have a distinct shiny look which is
called metallic luster.
4.03 Properties of Nonmetals
*As their name suggests,
NON-metals exhibit properties
that are just the opposite of metals.
*Non-metals are poor conductors of both electricity and
heat.
*Non-metals are generally used as insulators.
*At room temperature, non-metals can be either solids or
gases.
*Non-metals are not ductile.
*Non-metals are not malleable.
*Non-metals are mainly either opaque or transparent.
4.03 Properties of Metalloids
*The
physical properties of metalloids lie
between those of metals and non-metals.
*Metalloids are moderate conductors of
electricity.
*Metalloids are solid at room temperature.
*Metalloids can be ductile to varying degrees.
*Metalloids can be malleable to varying degrees.
*Metalloids can show a metallic luster in varying
degrees
4.03 Semiconductor
Semi means half or partial. So
semiconductors (metalloids) have electrical
conductivity half way between those of a
conductor and an insulator.
*
4.04Periodic Table
*The elements are arranged in order of
increasing atomic number.
*The elements are grouped in columns with
other elements with similar properties.
4.04Protons
Protons
*The positive subatomic particle
*The atomic number is the number of
protons in all atoms of the element
4.04 Electrons
*
Electrons-The negative subatomic particle
*The number of electrons equals the
number of protons in a neutral atom
*This means that the atomic number tells
us the number of electrons and protons
4.04 Neutrons
*
Neutron- The neutral subatomic particle
*The mass number minus the atomic
number tells you the number of neutrons in
an atom
4.04 Energy levels
Each electron is localized to a specific
area, the energy level, within the electron
cloud.
*
* Each electron is localized to a specific
area, the energy level, within the electron
cloud.
4.04 Valence electrons
*
These outermost electrons
*The number of valence electrons in the
outermost energy level of an element
determines if and how the element will
react with other elements.
4.04 Examples of Valence Electrons and
Energy Level
4.05 Compounds
A compound is formed when two or more
atoms combine together to form a new
substance with unique properties .
*
4.05 Ionic Compound
*An
ionic bond is the chemical bond that results from
an electrostatic attraction that occurs when metal
atoms lose electrons to nonmetal atoms.
*An ionic compound can also be called a salt . Table
salt, NaCl, is not the only salt! Ionic compounds have
high melting points, are solid at room temperature,
and usually dissolve well in water.
*You can identify a compound that contains ionic
bonds because it will contain atoms of a metal
bonded with atoms of a nonmetal. Examples include
NaCl, Al2O3, and CaCl2.
4.05 Ionic Compound
4.05 Covalent Compound
*A
covalent bond is a chemical bond that is
formed by the sharing of electrons between
atoms.
*Covalent compounds are also called molecules.
Molecules can be solids, liquids or gases at room
temperature. They also have much lower melting
points than ionic compounds.
4.05 Covalent Compound
*You
can identify a compound that contains
covalent bonds because it is made up of only
nonmetals. Examples include H2O, CO, CH4, and
NH3.
4.05 Covalent Compound
4.06 Properties of Compounds
*Acids
*Have a sour taste.
Grapefruit is an example of an acidic fruit.
*React with metals.
If you have ever encountered a corroded battery, you
have witnessed how acids react with metal.
*Can cause stinging on skin or membranes.
Heart burn is an example of stomach acid stinging the
lining of the esophagus.
4.06 Properties of Compounds
*An acid is a molecular compound that contains hydrogen and produces
hydrogen ions, H+, when it breaks apart in solution.
*HCl is hydrochloric acid. When it dissolves in water to make an acidic solution, it
breaks apart and gives off H+ particles.
HCl H+ + Cl-
*Other examples of acids include:
Sulfuric acid, H2SO4, which is found in batteries and acid rain
Acetic acid, HC2H3O2, found in vinegar
Citric acid, C6H8O7, found in citrus fruits like lemons and limes
*Everyday items that contain acids include:
Lemons
Oranges
Lettuce
Tomatoes
4.06 Examples of Acids
4.06 Properties of Compounds
*Bases
*Have a bitter taste.
Mustard and many medications are bitter
because of the bases they contain.
*Feel slippery to the touch.
Laundry detergent has a very slippery feel
because of its basic ingredients.
*Can be irritating to nose and eyes.
*Ammonia is an example of a base that can be
very irritating to the nose, eyes, and skin.
4.06 Bases
*A base is a compound that has OH in its formula and produces hydroxide ions,
OH-, when it breaks apart in solution.
*NaOH is sodium hydroxide, a base. When it dissolves in water the oxygen and
hydrogen atoms break off as OH-particles.
NaOH Na+ + OH-
*Other examples of bases include:
*Potassium hydroxide, KOH, is used in the production of soaps and biodiesel
*Calcium hydroxide, Ca(OH)2, is also known as lime. It is used in the production
of plaster, treatment of root canals, and many other industrial uses.
*Everyday items that contain bases include:
Soap
Toothpaste
Ammonia
4.06 Examples of Bases
4.06 Advance pH scale
An acidic solution has more H+ ions than
OH- ions.
*
*A neutral solution has equal amounts of
H+ and OH-.
*A basic solution has fewer H+ ions than
OH- ions.
4.06 Advance pH Scale
*The measure of the acidity of a solution is
called pH . This
measurement is based on the amount of hydrogen ions
present.
*If the pH of a solution is less than 7, it is acidic. The lower
the pH value is, the more acidic the solution because of
the greater amount of H+ ions.
*If the pH of a solution is 7, it is a neutral solution. This
means that the concentrations of H+ ions and OH- ions
are equal.
*If the pH of a solution is greater than 7, it is basic. The
higher the pH value, the more basic and the greater the
amount of OH- ions.
4.06 Advance pH Scale
*1.6 pH value - Stomach Fluid
*2.8 pH value - Vinegar
*4.2 pH value - Tomatoes
*5.0 pH value - Coffee
*7.0 pH value - Pure Water
*8.2 pH value - Sea Water
*9.2 pH value - Baking Soda
*11.4 pH value - Household Ammonia
*12.8 pH value - Household Bleach
4.06 Advance pH Scale
4.06 Advance Test Knowledge
*
High number of H+ ions - Acid
*Low pH value - Acid
*More H+ than OH- - Acid
*High pH value - Base
*High number of OH- ions - Base
*More OH- than H+ - Base
4.06 Are they a Solution, Compound or Mixture
*Salt - is a compound, and compounds are pure substances.
*Soda Water - is a mixture of gaseous carbon dioxide and liquid water.
*Mixture Brass - is an alloy or a mixture of metals.
*Brass is made from mixing the elements copper and zinc. Mixture
*Aluminum Foil - is a pure element, found on the periodic table. Pure
Solution
*Granite - is a mixture of different materials that create those neat patterns
in the rock. Mixture
*Iron - is a pure element found on the periodic table. Pure Solution
*Steel - is an alloy, a mixture of iron and carbon. Mixture
*Milk - is a mixture of water, fat, and other substances, such as calcium.
Mixture
4.07 Difference Between Heterogenous
and Homogenous Mixture
*homo-: This part of the word comes from the prefix hom-, which means
same. A homogeneous sample is the same throughout the sample.
*–geneous in homogeneous: This part of the word comes from the root
gen(os). In this context, it means kind. This helps us understand that a
homogeneous substance is of the same kind throughout. It is uniform in its
composition.
*hetero-: This part of the word comes from the prefix heter(o)-, which
means different or other. A heterogeneous substance is different in various
portions of the sample.
*–geneous in heterogeneous: This part of the word comes from the root
gen(os). In this context, it means kind. This links with the prefix to tell us that
a heterogeneous substance is of a different kind throughout. It is not
uniform in its composition.
4.07 Review
4.07 Review Pure Substance or Mixture
4.07 Mixtures, Solutions, and Pure Substances Practice
Classify each of the following as a solution, heterogeneous mixture, element or compound.
*A mixture that is uniform throughout - solution
*Alloys are an example - solution
*Marble is an example - heterogeneous mixture
*Aluminum is an example - element
*Sodium chloride is an example - compound
*A pure substance that can be broken down by chemical means - compound
*Sand and water is an example - heterogeneous mixture
*A pure substance that cannot be broken down - element
*Air is an example - solution
*Carbon is an example - element
*A mixture that is not uniform throughout - heterogeneous mixture
*Carbon monoxide is an example – compound
4.08 Physical Properties
These are examples of physical properties. Please read each word to learn more about it.
*Color
When you observe the color of an object, you are observing a physical property.
*Shape
The shape of a sample of matter can be observed and even changed without changing the
identity of the material. Ripping or folding a piece of paper does not stop it from being
paper.
*Phase/State
The phase (solid, liquid, or gas) of a substance is a physical property that can be observed
without changing the identity of the matter.
*Density
This ratio of mass per volume is a physical property that does not depend on the size of the
sample. You will be learning more about this physical property in a later lesson.
4.08 Physical Properties
*Mass
The measure (in grams or pounds) of the amount
of matter in an object is definitely a physical
property.
*Volume
The amount of space occupied by an object is a
physical property that can be measured in units
like liters or cubic centimeters.
4.08 Physical Properties
*Ductility
The ability to be pulled or stretched to make a wire is a physical property of
metals.
*Melting Point
The temperature at which a solid becomes a liquid is a physical property
unique to each type of matter.
*Malleability
The ability to be shaped, dented, or extended by beating with a hammer or
rolling is another physical property of metals. Have you ever bent a metal
spoon or put a dent in the door of a car?
4.08 Physical Properties
*
Boiling Point
*The temperature at which a liquid
becomes a gas is a physical property
unique to each type of matter.
4.08 Physical Properties - Extensive and
Intensive Physical Properties
*Extensive Physical Properties
*An extensive physical property depends on the amount of matter present
in the sample. Such properties include mass, length, shape, and volume.
These measurements will change depending on how large or small the
sample of matter.
*Intensive Physical Properties
An intensive physical property does not depend on the amount of matter
present in the sample. Such properties include melting point, boiling point,
density, ductility, malleability, and color. These properties will not change for
a given type of matter regardless of the sample size.
4.08 Physical Properties Practice Quiz
Read the following observations. Are they extensive properties or intensive
properties?
*His new car is blue. –Intensive
*Color does not depend on the size of the car. It could be a sports car or a
matchbox car!-Intensive
*She weighs 121 pounds.-Extensive
*Her weight would change if she were a different size.-Extensive
*The king-sized candy bar has 150 calories.-Extensive
*The amount of calories will change depending on the size of the candy bar.Extensive
4.08 Physical Properties Practice Quiz
The gold coin bends when the pirate bites it.-Intensive
*Malleability (the ability to bend) of gold does not depend on the amount of
gold or size of the coin.-Intensive
*The experiment produced 20.5 mL of solution. -Extensive
*The volume of the solution depends on the amount of matter present.Extensive
*The ice melted at zero degrees Celsius. –Extensive
*The melting point of a substance does not depend on the size of the
sample.-Intensive
4.09 Weight vs Mass
*Weight -is a measure of Earth’s gravitational
attraction for matter. This means that weight is
affected by both the amount of matter in the
object and the amount of gravity pulling on the
object. This is why the weight of an object
changes on different planets.
4.09 Weight vs Mass
Mass -is a measure of the quantity, or
amount, of matter in an object. This means
that the more matter there is in an object,
the greater its mass. Mass is not affected by
gravity. This is why the mass of an object
does not change on different planets.
*
*Formula
weight = mass x gravity
4.09 Mass, Density, and Weight
4.09 Weight vs Mass
4.10 Density
*Density
is:
*A ratio of mass per unit volume; or mass divided by
volume.
*An intensive physical property that is used to help
identify an element or compound.
*A property that is most commonly measured in the
units: g/mL, g/cm3, or g/L.
4.10 Density Quiz
*Given the mass and volume, calculate the density of each of the following:
*The mercury in a thermometer has a volume of 0.206 milliliters and a mass
of 2.8 grams. What is its density?
*Density = 2.8 g ÷ 0.206 mL = 13.6 g/mL
*A sample of mithril has a mass of 120 g and a volume of 60 mL. What is its
density?
*Density= 120 g ÷ 60 mL = 2 g/mL
*A sample of water has a volume of 24.0 milliliters and a mass of 23.8 grams.
What is its density?
*Density= 23.8 g ÷ 24.0 mL = 0.992 g/mL
Module 4 Review
Be sure to review:
*Atomic Theory.
*The history and use of the periodic table.
*The properties of compounds, mixtures, solutions and
pure substances.
*The difference between extensive and intensive physical
properties.
*The difference between weight and mass.
The properties of density.
Module 4 Review