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Unit 3
Periodic Table
Robert Boyle
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The first scientist to be
concerned with careful
measurements
Did not hold any
assumptions as to how
many elements there
were
Decided that only
experimentation would
tell
Element 101

Basic building blocks
 1 atom or many atoms of the same kind = an element
Presently there are about 120 elements
 88 occur naturally
The 9 most abundant make up 98% of the earth’s mass
 Oxygen 49%
 Silicon 25 %
 Aluminum, Iron, Calcium, Sodium, Potassium, Magnesium, and
Hydrogen

Diatomic molecules are ELEMENTS!
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Two atoms of the same element bonded together… know them!
Mendeleev's Periodic Table: The first one!
- Can you see any patterns?
- How was it arranged?
Build Your Own Table Time!!
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-
In groups of 2-3 you
will be building your
own tables
Be sure to write down
information that will
help you organize this
again!
What’s on the table?
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Atomic number
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Atomic Mass
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Number of protons
Defines the element
The average mass of all
the isotopes of that
element
Atomic Symbol
Name
Mass Number

The mass of a single
isotope of an element
Color Time!!!!!
Elemental Nomenclature
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Elemental name are
often derived from
Latin or Greek words
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Aurum – shining
dawn
Plumbum – heavy
Bromus - stench
26 Common Elements and Their
Symbols… You MUST know these!
Atomic Anatomy
-
Proton
-
-
Electron
-
-
p+
Nucleus
1 AMU
eElectron cloud
1/1847 AMU
Neutron
-
-
n
Nucleus
1 AMU
Using Your Table
Calculating Protons:
- Atomic number
- Same as electrons in neutral atoms
Calculating Electrons:
- Same as protons in neutral atoms
Calculating Neutrons:
- M# - A# = # of neutrons
- DO NOT USE atomic mass, must use mass #
Element Quiz
Provide the symbol for
the following elements:
Provide the name for the
following symbols:
1.
2.
3.
4.
5.
6.
7.
8.
9. Mg
10. Ag
11. Cr
12. I
13. Sn
14. F
15. S
16. Hg
Aluminum
Bromine
Potassium
Sodium
Lead
Copper
Nitrogen
Zinc
Spelling Does Count!
Atomic Structure Quiz

Provide the following 5 pieces of information for the
given atoms: #p+, #n0, #e-, mass #, atomic #
LOOK AT THE
CHALKBOARD!
Isotopes and the Nucleus

Isotopes are atoms with the same number of
protons, but different numbers of neutrons.
Do they have the same mass?

Are they the same element?

-Isotopes are described
by their mass number
-Examples:
-C-12 and C-14
How many protons?
How many neutrons?
Isotope Math
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Calculating Mass #
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Calculating Average Mass of given isotopes
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#n0 + #p+ = mass #
(sum of mass #s)/(# of atoms) = Ave Mass
Calculating Weighted Masses (by percent)
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(%A)(Mass #A) + (%B)(Mass #B) + …= Weighted Mass
Try Some!!
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Calculate Average Mass
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1 atom has a mass of 10
1 atom has a mass of 12
1 atom has a mass of 8
30/3=10 AMU
5 atoms have a mass of 10 each
17 atoms have a mass of 12 each
3 atoms have a mass of 8 each
278/25 = 11.1 AMU
5 x 10 = 50
17 x 12 = 204
3 x 8 = 24
= 278
One more!
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39% have a mass of 10 AMU
11% have a mass of 12 AMU
50% have a mass of 8 AMU
Total
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3.9 + 1.32 + 4 = 9.22 AMU
Isotopes of B WS
From the Nucleus to the Cloud
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Electrons are negatively
charged
Electrons are virtually
massless
Electrons are FAST!
Electrons are quantized

Electrons inhabit orbitals
(aka rings or shells)
Outer Atomic Structure
-
Electrons “live” outside the nucleus
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-
Electron Shells (Bohr)
Electron Cloud (Schrodinger)
The outermost electrons are valence electrons
All other electrons are core electrons
Core e- = (Atomic #) – (Valence e-)
The importance of valence
electrons
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Valence electrons are on
the outer shell
They are the electrons that
are involved in reactions
We can describe chemical
behavior by knowing the
number of valence
electrons
Perioic table and
electrons… using your
table again!
Ions
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Ions are atoms that are
no longer neutral, they
have a charge
Electrons can be
removed or added
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Removed = +
Added = -
Ions are usually
unstable and very
reactive
Ground State Electron
Configurations
The “address” for the electron in a
neutral atom
Electron Questions
1.
2.
What is the “address” for electrons in an
atom?
How can we find the electron’s “address”
Use the following terms in 2-4 sentences that describe how we can find
the following on the periodic table. You may work with 1 partner.
Valence shell
Valence electrons
Core electrons
Groups
Periods
Shells
Purple – The final electrons for these elements are in the “s” orbital
Pale Yellow – The final electrons for these elements are in the “p” orbital
Teal – The final electrons for these elements are in the “d” orbital
Light Green – The final electrons for these elements are in the “f” orbital
Orbital Filling - Aufbau Principle
-Electrons will fill the LOWEST
energy levels first.
-This is known as the Aufbau
(building up) principle.
-Electron filling follows the
diagram
“s” orbitals can hold up to 2 electrons
“p” orbitals can hold up to 6 electrons
“d” orbitals can hold up to 10
electrons
“f” orbitals can hold up to 14 electrons
The order ends up:
1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d107p6
NOTICE: Certain orbital types ONLY
show up in certain shells
Electron Configurations and Dot
Diagrams:
Show the electron configuration and dot diagram for
the following:
Li
O
Be
Ne
Na
Ti
Models of the Atom
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Solid Model (Dalton)
Plum Pudding Model (Thomson)
Rutherford Model
Bohr Model
Cloud Model (Schrodinger)
Dalton’s Atomic Theory
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English Science
teacher in the 1800’s
Offered a 5 part
theory for the
structure of an atom
Dalton’s Theory
1.
2.
3.
4.
5.
Elements are made up of small particles called atoms.
All atoms of a given element are identical.
The atoms of a given element are different from those of any
other element.
Atoms of one element can combine with atoms from another
element to form compounds. A given compound always has
the same relative numbers and types of atoms.
Atoms are indivisible in chemical processes. That is, atoms
are not created or destroyed in chemical reactions. A
chemical reaction simply changes the way atoms are
grouped together.
Plum Pudding Model
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Proposed by J.J. Thomson
in the 1800’s
First experimental proof
of different charges in an
atom
Said the atom looked like
“pudding with plums in
it”
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Plums were the evenly
distributed positive and
negative charges.
Rutherford’s Model
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Proof of a solid nucleus
Most particles moved
through the foil
untouched
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Foil was mostly empty
space
Some particles were
deflected
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There must be a solid,
dense nucleus with a
positive charge
Niels Bohr’s Model of the Atom
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Based on data obtained from
the atomic spectrum
Electrons must be
“quantized”
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Only inhabit specific levels of
energy (quanta, orbitals)
Must be several levels
Atoms can jump from one
level to another, but cannot
inhabit in between levels
Incorporated ideas from
Quantum Physics
Bright Line Spectrum of Hydrogen
Schrodinger’s Cloud Model
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Schrodinger was a
physicist
Calculated the probability
of an electron being in
each level
Plotted the probabilities
and determined a function
to calculate the position or
energy of an electron
This is the model most
scientists refer to today