Download Periodic Table for class

MATTER: Atomic Structure
Elements
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The elements, alone
or in combinations,
make up our bodies,
our world, our sun,
and in fact, the entire
universe.
Definition: a
substance that cannot
be broken down into a
simpler substance by
chemical means..
The most abundant element in the
earth’s crust is oxygen.
90 elements occur naturally on earth. The others have been created in labs.
What is an atom?
The smallest unit of an element
 They can’t be broken down
 Atoms are so small we could fit over a
million atoms inside this period .
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Subatomic Particles
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Protons and electrons are the only particles that have a
charge.
PROTONS have a (+) positive charge (in nucleus)
ELECTRONS have a (-) negative charge
NEUTONS have no charge (in nucleus)
Protons and neutrons have essentially the
same mass.
 The mass of an electron is so small we
ignore it.
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The Nucleus
The protons and neutrons packed closely
together make up the nucleus
 Located in the CENTER of the atom
 It is Positively charged
 Makes up most of the mass but not
volume
 EXAMPLE: Gumdrop/Football stadium
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Electron Cloud
Electrons move inside this region
 Since opposite charges attract each other
 The negative (electrons) are attracted to
the positively charged nucleus
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Atomic Number
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The number of
protons in the
nucleus is called the
atomic number.
No two elements,
have the same
number of protons.
Bohr Model of Hydrogen Atom
Wave Model
Atomic Number
Atomic Mass
The mass of an atom in atomic mass units (amu)
is the total number of protons and neutrons
in the atom.
Atomic Mass
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Atomic Mass refers to
the “weight” of the
atom.
It is derived at by
adding the number of
protons with the
number of neutrons.
HOW TO READ THE
PERIODIC TABLE
How to find protons:
The number of protons equals the atomic
number
 How to find neutrons:
1. Find the atomic weight of the element
2. Find the number of protons of the
element
3. Subtract the number of protons from the
atomic weight of the element
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How to find the electrons and rings:
1. Find the electrons in each ring at the
bottom of your element
2. The number of electrons on each ring is
given from left to right
3. The first number on the left represents
the first ring outside of the nucleus
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Introduction
The periodic table is made up of rows of elements
and columns.
 An element is identified by its chemical symbol.
 The number above the symbol is the atomic
number
 The number below the symbol is the rounded
atomic weight of the element.
 A row is called a period
 A column is called a group
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Names of Elements
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The first 103 elements have internationally
accepted names, which are derived from:
 The
compound or substance in which the element was
discovered
 An unusual or identifying property of the element
 Places, cities, and countries
 Famous scientists
 Greek mythology
 Astronomical objects.
Dmitri Mendeleev
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Russian scientist born in Siberia in 1834,
is known as the father of the periodic
table of the elements.
The periodic table of the elements is an
important tool used by students and
chemists around the world to help them
understand and simplify the often
complex world of chemical reactions.
Not only did Mendeleev arrange the
periodic table of the elements, he also
wrote and published a 2 volume
chemistry book entitled Principles of
Chemistry as there was no thorough
chemistry textbook at the time.
The Big Task
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Mendeleev set out to identify a pattern in the
elements.
Mendeleev looked at many pieces of evidence
and made an important observation that some
elements have similar chemical and physical
properties.
Mendeleev's hunch was that these similarities
were the key to unlocking the hidden pattern of
the elements.
Mendeleev then embarked on the tedious task
of organizing all known information for every
element to help him decipher the pattern.
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To begin his task, Mendeleev wrote facts about the
elements on individual paper cards. On these cards,
Mendeleev wrote information such as the elements'
melting points, densities, colors, atomic masses (the
average mass of one atom of that element), and bonding
powers (the number of chemical bonds an element can
form).
Once Mendeleev's cards were made, he tried arranging
them in various ways. Finally, Mendeleev noticed that
patterns appeared when the elements were arranged in
order of increasing atomic mass.
Mendeleev's table was not perfect, however. Arranging
the elements by increasing atomic mass left three blank
spaces in the table.
This first periodic table of the elements was published in
1869.
The word "periodic" means that there is a
repeating pattern -- that is, the properties
of the elements repeat with each row -- or
period -- of the table.
 Amazingly, within 16 years of Mendeleev's
first periodic table, chemists had
discovered all three of the missing
elements (scandium, gallium, and
germanium), and their properties were
very close to what Mendeleev had
predicted.
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Periodic Table
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The rows on the periodic
chart are periods.
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The period tells you which
shell with the highest
energy is being used by that
atom. So every atom in the
third period aka the third
row is using up to the third
shell of their shells of
electrons.
Columns are groups.
Elements in the same
group have similar
chemical properties.
Today there are 111 elements recognized by IUPAC
(International Union of Pure Applied Chemistry )
Groups
These five groups are known by their names.
Periodic Table
Nonmetals are on the
right side of the
periodic table (with
the exception of H).
Periodic Table
Metalloids border the
stair-step line (with
the exception of Al
and Po).
Periodic Table
Metals are on the left
side of the chart.
Symbols
C
Cu
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Carbon
Copper
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All elements have
their own unique
symbol.
It can consist of a
single capital letter, or
a capital letter and
one or two lower case
letters.
Calculating the # of electrons in
each shell
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In other words, electron shells have a limited capacity for
electrons.
As you might expect, the farther an electron shell is from
the nucleus, the larger it is.
You can calculate the total capacity of an electron shell
using the formula 2n2, where n equals the number of the
electron shell.
For example, for the 1st electron shell n = 1 and 2 x 1x1
= 2, telling us that the capacity of the 1st shell is 2
electrons as we have already seen.
For the 2nd shell (n = 2) and 2 x 2x2 = 8. For an atom to
fill its 2nd electron shell, it would need 10 electrons: 2 to
fill the 1st shell and 8 to fill the 2nd.
The 3rd shell has a total capacity of 2 x 3x3 = 18
electrons.
Shell
Number
2 * (the shell number * the
shell number)
= the maximum number of
electrons in this shell.
Maximum Number
of Electrons in the
Shell
1
2 x (1 x 1) = 2
2x1=2
2
2 x (2 x 2) = 8
2x4=8
3
2 x ( 3 x 3) = 18
2 x 9 = 18
4
2 x (4 x 4) = 32
2 x 16 = 32
5
2 x (5 x 5) = 50
2 x 25 = 50
There are five possible shells
available to atoms. This diagram
shows only three shells, and some
atoms, such as the little hydrogen
atom, use only the one inner shell.
Each of the elements has a
different number of the tiny
electrons, and a corresponding
number of protons. Hydrogen is the
smallest, with only one electron.
Carbon, nitrogen, and oxygen, are
also small, light atoms.
Get a white piece of paper
Select 4 elements
Draw the atomic model for each
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Element 5: Boron
Element 6: Carbon
Element 7: Nitrogen
Element 8: Oxygen
Element 9: Fluorine
Element 10: Neon
Element 11: Sodium
Element 12: Magnesium
Element 13: Aluminum
Element 14: Silicon
Element 15: Phosphorus
Element 16: Sulfur
Element 17: Chlorine
Element 18: Argon
HW choose 3 elements
Tell me how many protons, neutrons and
electrons
 Draw a diagram of the element and color
code it
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Valence Electrons
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The number of valence
electrons an atom has
may also appear in a
square.
Valence electrons are the
electrons in the outer
energy level of an atom.
These are the electrons
that are transferred or
shared when atoms bond
together.
Valence electrons
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The outer shell electrons that are available
for and capable of forming bonds with
other atoms. Valence electrons are
electrons occupying the outermost energy
level.
Properties of Metals
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Metals are good conductors
of heat and electricity.
Metals are shiny.
Metals are ductile (can be
stretched into thin wires).
Metals are malleable (can be
pounded into thin sheets).
A chemical property of metal
is its reaction with water
which results in corrosion.
Properties of Non-Metals
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Sulfur
Non-metals are poor
conductors of heat and
electricity.
Non-metals are not
ductile or malleable.
Solid non-metals are
brittle and break easily.
They are dull.
Many non-metals are
gases.
Properties of Metalloids
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Silicon
Metalloids (metal-like) have
properties of both metals and
non-metals.
They are solids that can be
shiny or dull.
They conduct heat and
electricity better than nonmetals but not as well as
metals.
They are ductile and
malleable.
Hydrogen
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The hydrogen square sits atop Family IA,
but it is not a member of that family.
Hydrogen is in a class of its own.
It’s a gas at room temperature.
It has one proton and one electron in its one
and only energy level.
Hydrogen only needs 1 electron to fill up its
valence shell.
Alkali Metals
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The alkali family is found in
the first column of the
periodic table.
Atoms of the alkali metals
have a single electron in
their outermost level, in other
words, 1 valence electron.
They are shiny, have the
consistency of clay, and are
easily cut with a knife.
Alkali Metals
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They are the most
reactive metals.
They react violently
with water.
Alkali metals are
never found as free
elements in nature.
They are always
bonded with another
element.
What does it mean to be
reactive?
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Elements that are reactive bond easily with other
elements to make compounds.
Some elements are only found in nature bonded
with other elements.
What makes an element reactive?
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An incomplete valence electron level.
All atoms (except hydrogen) want to have 8 electrons
in their very outermost energy level (This is called the
rule of octet.)
Atoms bond until this level is complete. Atoms with
few valence electrons lose them during bonding.
Atoms with 6, 7, or 8 valence electrons gain electrons
during bonding.
Ions
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When atoms lose or gain electrons, they become
ions.
Ions are atoms with either extra electrons or missing
electrons. A normal atom is called a neutral atom.
That term describes an atom with a number of
electrons equal to the atomic number.
If an atom has the same number of protons
and electrons, it is electrically neutral. If
electrons are added or removed, the atom
(now called an ion) becomes charged
Example
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Sodium (Na) atom
has eleven electrons
one too many in her outer shell
she needs to find another element who will take
that extra electron away so she can be complete
(filled electrical orbital's)
Bring in chlorine (Cl).
Chlorine (Cl) will take that electron away and
leave her with 10 electrons inside of two filled
shells. She is now a happy atom.
Now she is an ion and missing one
electron.
 She is now sodium ion (Na+). She has
one less electron than your atomic number
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Now with filled shells.
 Sodium is a stable atom. LOST one (+)
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positively charged ion
Chlorine GAINED one (-) negatively charged ion
 What do you do that's so special now?
Now that you have given up the electron,
you are quite electrically attractive. Other
electrically charged atoms (ions) are now
looking at you and seeing a good partner
to bond with.
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The Oppositely charged ions attract each
other and form an ionic bond
Cations are positive ions and are formed by
elements on the left side of the periodic chart.
 Removing electrons from the atom results in a
positively charged ion,
 Anions are negative ions and are formed by
elements on the right side of the periodic
chart.
 Adding electrons results in a negatively
charged ion
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BONDIING
There are two main types of bonding
 Electrovalent/ Ionic and Covalent
 Ionic Bonds = the attractive force
between oppositely charged ions that
result from the transfer of electrons from
one atom to another.
 If a compound is formed through the
transfer of electrons its called Ionic
Compound (NaCl)
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Positive because
now the atom is
more positively
charged it has 11
protons & 10
electrons
Negative because
now Cl has an extra
negative charge and it
will make it more
negative
Covalent Bonds= form when atoms share
one or more pairs of electrons.
 The nucleus of each atom is attracted to
the shared electrons & keeps it together
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Ionic Bonds
Ionic compounds (such as NaCl) are
generally formed between metals and
nonmetals.
Chemical Bonding
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Two types of bonding
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Ionic bonding
Covalent bonding
Polar covalent
Metallic
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OPEN PPT on Desktop CHEMBOND
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Isotopes:
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Atoms of the same element with different # of
neutrons.
Isotopes have different numbers of neutrons.
11
C
6
12
C
6
13
C
6
14
C
6
Some isotopes are stable, while others are radioactive—they
eventually break down and release particles or energy called
radiation.
Let's say an atom is missing a neutron or
has an extra neutron.
 That type of atom is called an isotope.
 An atom is still the same element if it is
missing an electron. The same goes for
isotopes. They are still the same element.
They are just a little different from every
other atom of the same element.
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Elements, Compounds,
Mixtures
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Sodium is an element.
Chlorine is an element.
When sodium and
chlorine bond they
make the compound
sodium chloride,
commonly known as
table salt.
Compounds have different properties
than the elements that make them up.
Table salt has different properties than
sodium, an explosive metal, and chlorine,
a poisonous gas.
Dalton’s Postulates
1. Every element is composed of tiny particles called atoms
2. All atoms of a given element are identical
1. Atoms of different elements have different properties
3. Atoms of an element are NOT changed into atoms of
another element by chemical processes
1. Matter can neither be created nor destroyed
4. Compounds are formed when atoms of more than one
element combine