Download Target 3 – Identify the 3 main classes of

Periodicity and the Quantum Electron Model
Chapters 5 and 6
Part A – THE BASICS OF
PERIODIC TABLE
Target 1 – Explain how elements are arranged on
the periodic table based on similarities.
A. Elements are arranged on the periodic table based
on similarities.
B. At a grocery store, you find food items located
around the store based on similarities. Fruits are
with fruits, and meats are with meats – and so
forth.
C. So what about atoms? How can they be
grouped based on similarities?
D. As elements were discovered over the
centuries, chemists began to notice certain
properties.
E. For example, when Chlorine, Bromine, and
Iodine were discovered, scientists noticed
that all 3 of these elements react easily
with metals.
F. Notice that chlorine, bromine, and iodine
are all in group 7. (just like a grocery
store)
G. After all of the major discoveries, it was
decided that the order of the periodic table
would be based on the atomic number
(protons).
Target 2 – Identify Groups
and Periods on the Periodic
Table.
A. The periodic table is based on groups and
periods.
B. Groups run vertical. For example, Group 1
contains Hydrogen, Lithium, Sodium,
Potassium…
1. Elements in the same group will have the
same number of valence electrons.
2. Elements that are in the same group will
have similar properties.
3. Example 1, the elements in group 1 will all
explode when placed in water.
4. Example 2, the elements in group 7 will
react easily with metals.
C. Periods run horizontal. For example,
Period 2 contains Lithium , Beryllium,
Boron, Carbon…
1. Elements in the same period will have the
same number of energy levels.
2. Elements in the same period will NOT
have similar properties
questions
Target 3 – Identify the 3 main
classes of elements on the
periodic table
A. There are 3 main classes of elements on
the periodic table.
1. Metals
2. Non-Metals
3. Metalloids
Target 4 – List the properties of
each class of elements on the
periodic table.
A. Metals
1. Good conductor heat and electricity
2. Shiny luster when cleaned
3. Solid at room temperature
4. Malleable and ductile
B. Non-metals
1. Poor conductor of heat and electricity
2. If not a gas, they usually have a dull luster
(not shiny)
3. Usually a gas at room temperature
4. Brittle
C. Metalloids
1. Metalloids have properties similar to both
metals and non-metals.
2. Sometimes they behave like a metal,
sometimes like a non-metal.
Target 5 – Identify the Families
on the Periodic Table (pg
162)
A. The periodic table can be broken down into
10 families.
B. Elements found in the same family will
have similar properties.
C. Insert families periodic table
Target 6 - Identify the 4 blocks
on the periodic table
The periodic table can be divided up into 4
blocks – based on electron configurations.
questions – 2min 37.2 secs
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Part B – TRENDS ON THE
PERIODIC TABLE
Target 7 – Define the word
“Trend” and give examples.
A. A trend is an occurrence in nature that usually
happens, but not always; general tendency or
direction.
B. Trend 1: Learning occurs more in classrooms
where there is a lot of order. (positive
relationship)
C. Trend 2: Weight loss occurs more when people go
out and exercise. (inverse relationship)
List some other trends
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Target 8 – Define diatomic and explain
how the radius (size) of an element can
be calculated.
A. It is difficult to measure the size of an atom because the
outer boundary is made of electrons flying around the
nucleus.
B. The current theory of atoms is that they are spherical in
shape.
C. Some atoms are diatomic – which means two atoms of the
same element bond together.
D. There are seven common diatomic elements. H2, O2, N2 ,
F2, Cl2, Br2, I2
E. The diagram below lists the radii of the seven common
diatomic elements
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F. Because two atoms of the same element
must be the same size, the size of an atom
can be calculated by knowing the distance
between the two nuclei.
G. The size of an atom is measured by its
radius.
H. Atomic radius is one half of the distance
between the nuclei of two atoms of the
same element when the atoms are joined.
I. The atomic radius is measured in
picometers(pm)
J. One picometer is one trillionth of a meter
(10-12 meters or 0.00000000001 meters)
K. For example, the distance between the
nuclei in an iodine molecule (I2) is 280
pm, therefore the radius of one iodine
atom is 140 pm.
notes – radius of 2 attached circles
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L. If you know the radius of a sphere, you can
calculate the volume(size).
M. Remember from earlier that the volume of
a sphere can be calculated with this
formula 4/3πr3
N. The volume of each element is not
important in this class – you may choose
to calculate that on your own time.
O. The important thing to realize is that the
radius of an atom is proportional to its size
(volume).
questions
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Target 9 – Explain the trends of
the atomic radius of various atoms
on the periodic table.
A. Moving down the periodic table
1. As you move down vertically on the periodic table
in a group, the atomic radius INCREASES.
2. Why? As you go down the periodic table, the
number of energy levels increase.
3. Example 1: Potassium has 4 energy levels and
Sodium has 3 energy levels – therefore potassium
is a larger atom than sodium.
notes
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B. Moving across the periodic table
1. As you move across a period from left to right, the
atomic radius DECREASES.
2. Why? As you go across the periodic table, the
atomic number increases by one proton.
3. Remember that one proton has a charge of
+1…As the charge of the nucleus increases as you
move across a period, it creates a stronger pull on
the electrons.
4. This stronger pull of electrons draws them in
closer to the nucleus, and therefore causes overall
size of the atom to decrease.
notes
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questions
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Target 10 – Define ion and explain
how they are formed.
We learned earlier that the atomic number will tell
you how many electrons an atom will contain.
This is true in some cases.
In most cases, elements will not have the same
amount of protons as electrons.
Therefore, the atomic number does not give you an
accurate count of electrons.
A.
Sometimes atoms gain electrons and sometimes
atoms lose electrons.
Ion – an atom with a different number of protons and
electrons – resulting in an overall positive or
negative charge.
In other words, an atom with a charge is called an
“ion” not an “atom”
When an atom loses electrons, it becomes positively
charged – this is called a cation
When an atom gains electrons, it becomes negatively
charged – this is called an anion.
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notes cation/anion
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Target 11 - Explain how ions can
be different sizes than their
component atoms.
Again - Atoms that have a charge (positive or
negative) are called ions.
Ions will be of a different size than it’s component
atom – why is this?
Example 1, when sodium loses an electron, it has
more protons than electrons. Therefore the
overall electron cloud is pulled in closer to the
nucleus – thus the size of the atom decreases.
Illustrated below.
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notes - potassium
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Example 2: When a chlorine atom gains an
electron, it has more electrons than protons.
Therefore the overall electron cloud is
released – just a little, from the nucleus –
thus the size of the atom increases.
Illustrated below.
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notes fluorine
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E. Cation Trend – Cations are smaller than
their component atoms. For example, a
potassium cation is smaller than a
potassium atom.
F. Anion Trend – Anions are larger than their
component atoms. For example, a
fluorine anion is larger than a fluorine
atom.
questions
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Target 12 – Explain how ionization energy
can create an ion.
A. Electrons are not always limited to their proper
energy level.
B. If you add the appropriate amount of energy, an
electron can jump to a higher energy level.
C. Sometimes, if enough energy is added, electrons
can completely jump from the atom – creating
an ion – this is called ionization.
notes
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D. The energy required to remove an electron
from an atom is called “ionization
energy.”
E. There are several electrons in most atoms,
therefore, we must be more specific.
F. The energy required to remove the first
electron from an atom is called “first
ionization energy.”
G. The energy required to remove the second
electron from and atom is called “second
ionization energy.” Third ionizations also
exist (and so forth)
H. Typically, the first ionization is the easiest
– requiring the least amount of energy.
I. The second and third ionization energies
require more energy.
J. The unit for this measurement is KiloJoule
per Mole (KJ/mol) (The mole explanation
will come later)
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Target 13 - Explain the trends of
ionization energy of various atoms
on the periodic table.
A. As you move down a group, the ionization
energy decreases.
B. Why? As you move down a group, the
atomic size increases – this creates a lot of
space between the nucleus and the
electrons. Therefore, it is easier to remove
an electron.
C. As you move across a period – from left to
right, the ionization energy increases.
D. Why? As you move across a period – from
left to right – the atomic size decreases.
This creates less space between the
nucleus and the electrons. Therefore it is
harder to remove an electron.
notes
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questions
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Target 14 – Define Electronegativity and explain the
trends of electronegativity on the periodic table.
A. Electronegativity – the ability of an atom
to attract electrons when the atom is
bonded in a compound.
notes
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Example of water and carbon dioxide
B. Electronegativity is measured in units
called “Paulings” named after the inventor
of the concept Linus Pauling.
C. The range of Paulings 0 – 4.
D. The element with the lowest
electronegativity is Cesium (0.7 Paulings)
and the element with the highest
electronegativity is Fluorine (4.0
Paulings).
E. As you move down the periodic table,
elecronegativity decreases.
F. As you move across the periodic table from
left to right, electronegativity increases.
G. Learning why requires more detailed
understanding and is not part of this
course – just know the trend.
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