Atomic Structure
History of atomic theory
Basic subatomic particles
Isotopes
Relative abundance
Levels, sublevels and orbitals
Electron confiurations
Orbital diagrams
Periodic trends
The 6 Models
Democritus
John Dalton
J.J. Thomson
Ernest Rutherford
Niels Bohr
The Wave or Cloud
Model
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Greek philosopher that
came up with the the idea of
the atom (first atomic
theory).
In Ancient Greece (~400
B.C.)
Atomos… Meaning
indivisible or uncuttable
Would matter fall apart when
kicked like sand castles?
of matter.
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Aristotle – More famous philosopher
All substances are made of 4
elements
Fire - Hot
Air - light
Earth - cool, heavy
Water - wet
Blend these in different proportions
to get all substances
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Greek society was slave based.
Beneath famous to work with hands.
Did not experiment.
Greeks settled disagreements by
argument.
Aristotle was more famous.
He won.
His ideas carried through middle
ages
Democritus’ Atomic Model
Atoms are solid spheres.
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Alchemy is an ancient tradition, the primary objective of
which was the creation of the mythical "philosopher's
stone," which was said to be capable of turning base metals
into gold or silver, and also act as an elixir of life that
would confer youth and immortality upon its user.
Alchemy was a precursor to modern chemistry, having
provided procedures, equipment, and terminology that are
still in use.
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Jabir Ibn Hayyan aka Geber- 8th cent….. aqua regia
Zosimos
Albertus Magnus (1193–1280) and Thomas Aquinas (1225–
1274) …. reconciling the differences between philosophy and
Christianity. Aquinas also did a great deal of work in
developing the scientific method. He even went as far as
claiming that universals could be discovered only through
logical reasoning, and, since reason could not run in
opposition to God, reason must be compatible with theology.
contrary to Platonic belief of divine illumination alone.
Roger Bacon 13th cent …Franciscan view… sci method
Nicholas Flamel 14th cent writings
Paracelsus….Theophrastus Bombastus von Hohenheim 15th
cent… iatrochemistry
During the 17th century, Robert Boyle, the "father of modern
chemistry". In his book, The Skeptical Chymist, Boyle attacked
Paracelsus and the natural philosophy of Aristotle. …gases
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John Dalton- ~1800 in England.
His was the first MODERN Atomic Theory
 All matter is made of tiny indivisible
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particles called atoms.
Atoms of the same element are
identical, those of different atoms are
different.
Atoms combine in whole number
ratios to form compounds.
Chemical reactions involve the
rearrangement of atoms. No new
atoms are created or destroyed.
Dalton’s Model
Atoms are solid spheres and
each element is different.
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More atoms in a glass or water
than all the sand in the world!!
10 million would fit across the
head of a pin!!
An atom is the smallest particle of
an element that retains the
properties of that element
1.
2.
3.
4.
5.
Who developed the first atomic theory?
Who developed the first modern atomic
theory?
Draw Dalton’s atomic model.
Give any one of Dalton’s postulates.
Look at the PT, how many electrons are in
Dalton’s atomic model of CARBON?
J.J. Thomson
The English
scientist
who
discovered
Electrons in
1897.
Taught at Cambridge University.
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How did he discover this?
He used a piece of equipment called a cathode
ray tube (aka Crooke’s tube). Pg 107
Some TV’s and monitors:
Voltage source
-
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All the air has been
pumped out.
The anode (+) and
the cathode (-) are
connected to a
battery.
+
Vacuum tube
Metal Disks
Crooke’s
tube or
Cathode
ray tube
Voltage source
-
+
Thomson’s Experiment
Voltage source
 Passing
+
an electric current makes a
beam appear to move from the
negative to the positive end
Thomson’s Experiment
Voltage source
 Passing
+
an electric current makes a
beam appear to move from the
negative to the positive end
Thomson’s Experiment
Voltage source
 Passing
+
an electric current makes a
beam appear to move from the
negative to the positive end
Thomson’s Experiment
Voltage source
+
 By
adding an electric field he found
that the moving pieces were negative
Thomson’s Experiment
Voltage source
+
 By
adding an electric field he found
that the moving pieces were negative
Thomson’s Experiment
Voltage source
+
 By
adding an electric field he found
that the moving pieces were negative
Thomson’s Experiment
Voltage source
+
And the negatively charged electrons are
attracted to the positive pole of a magnet,
and repelled by the negative pole of a
magnet.
Like plum
pudding or
chocolate
chip cookie
dough
electrons
Thomson’s Model
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http://www.youtube.com/watch?v=XU8nMK
kzbT8&feature=related
Cathode ray
Can you do better?
http://www.youtube.com/watch?v=JwdGFZ
A3WOs&feature=related
http://www.bing.com/videos/search?q=croo
kes+tube&view=detail&mid=9F3C84426C38
EB5B8C549F3C84426C38EB5B8C54&first=
0&FORM=LKVR38
28
Ernest Rutherford
The English
scientist who
discovered the
Nucleus ~1911.
Born: New Zealand, was
Thomson’s student
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Believed in the plum pudding model of the
atom.
Wanted to see how big they are.
Used radioactive Alpha particles - positively
charged pieces- helium atoms minus electrons
Shot them at gold foil which can be made a
few atoms thick.
All around was a screen covered with zinc
sulfide.
The alpha particles hitting it would make a
flash of light.
Lead
block
Uranium
Fluorescent
Screen
Gold Foil
What he expected
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…... alpha particles to pass through without changing
very much.
…the positive charges were thought to be spread out
evenly.
He thought the mass was evenly
distributed in the atom
So alpha
radioactivity should
pass thorough.
What he got
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Atom is mostly empty with a small dense, positive nucleus at
center. Most alpha particles go straight through.
Alpha particles are deflected by it if they get a bit close.
They will bounce backwards if come very close .
+
How he explained it
Pretend you
are
Rutherford
and try
to guess
what the
unknown
shape is
Were you right?
Rutherford Model
Mostly empty
space with a
small, heavy,
positive nucleus
and negative
electrons around
the outside.
http://www.youtube.com/wat
ch?v=5pZj0u_XMbc&feature
=related
http://www.youtube.com/wat
ch?v=WK7wuTwAiBU&feat
ure=related atom history
song
Niels Bohr
1913
The Danish
scientist who
discovered
energy levels
of the
electrons.
Bohr proposed that each electron
moves in a specific energy level
around the nucleus, like planets
moving around the sun.
Electrons can absorb energy and
jump to other levels and jump back
giving off photons.
Bohr’s Model
What element?
Protons in
the nucleus,
electrons
arranged in
up to 7
energy
levels.
Wave or Cloud Model
The work of several scientists like Werner
Heisenberg (uncertainty principle) and Erwin
Schrödinger (electrons are waves), circa
1932.
Electrons are in 7 different energy clouds surrounding
the nucleus.
The probable location of an electron is based
on how much energy it has.
(more energy, the farther from the nucleus)
The
Wave
Model
Due to the wavelike character of electrons and
provides the framework for viewing the electrons as
fuzzy clouds of negative charge. Each energy level
has sublevels (s, p, d, f) with different shaped
“clouds”, then orbitals, etc.
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Over 200 different subatomic
particles have been found like
baryons, hadrons, neutrinos, antineutrinos, leptons, mesons, etc.
Most important: the quark; protons
and neutrons are made of this tiny
particle (smallest of all found so far.)
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Millikan – 1868-1953 – American physicist
“Oil drop experiment” (-) charged oil
droplets suspended in a chamber by
a certain electrical voltage – he could
then calculate the exact charge on the
droplet when it became motionless
 In 1909 – mass of e- is 1/2000 the
mass of one H atom
 mass of e- = charge of e- / charge to
mass ratio of e proved e- has smallest possible –
electrical charge (about 1 or more epresent in atoms of all elements)
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Chadwick – 1891-1974 – English scientist that
worked w/ Rutherford
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1932 he discovered neutrons
He hit Be atoms w/ + charged
He and found a particle w/ no
charge inside the nucleus –
called it a neutron
“I realized that a nuclear
bomb was not only possible, it
was inevitable. I had then to
start taking sleeping pills. It
was the only remedy."
Helped with the Manhattan
Project
References
•encarta.msn.com/encyclopedia
•www.funsci.com/fun3_en/democritus/democritus
•www.aare.edu.au
•www.absoluteastronomy.com/encyclopedia
There are 3 types of subatomic particles.
electrons (e–) & protons (p+).
Neutrons (n0) were also shown to exist (1930s).
Are ~ 200 subatomic particles
Smallest is quark
Atomic number…..
16
Atomic mass…..
Mass number….
E.g. Oxygen:
8
Isotope…
Isotope symbol…

Write the isotope symbol for gold-198

# of protons = # of electrons = atomic number

# of neutrons = mass number – atomic number
 Calculate # of e–, n0, p+ for C and C-14, and Cu.
 Ions….
 Cations….
 Anions….
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O
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Basic: must know the # of protons, neutrons, and
electrons (2,8,8,2 filling order)
Draw electrons around in shells (7 max)
He
p+
2
2 n0
Li
Li shorthand
3 p+
4 n0
3 p+
4 n0
2e– 1e–
Atoms of the same element that have different
numbers of neutrons are called isotopes.
 Due to isotopes, mass #s are not round #s.
 Li (6.94) is made up of both 6Li and 7Li.
 Often, at least one isotope is unstable.
 It breaks down, releasing radioactivity.
 These types of isotopes are called radioisotopes
 The atomic # of an element doesn’t change
Although the number of neutrons can vary, atoms
have definite numbers of protons.
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Relative abundance of isotopes
Element X has 2 isotopes. One has a mass of
10.012 amu at 19.91%
The other has a mass of 11.009 amu at 80.09%.
Calculate the atomic mass of the element.
Prob 2 Carbon’s isotopes are C-12 (12.000 amu,
98.89 %) and C-13 (13.003 amu and 1.11%)
Calculate the atomic mass of carbon.
1.
Draw Bohr’s model for Br (35)
___p
___n
2.
3.
4.
5.
Energy levels
Isotope symbol for silver-109
The number of neutrons in average atom of P
is __________
Difference between mass number and atomic
mass is…..
Difference between an ion and an isotope…..
Chem textbook (red)
 Restate the question
 Pg 61 #1-14
 Pg 122 # 46-56
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AP text book (silver)
Restate question
Pg 29 read it
Pg 30:
Q #: 1, 2, 5, 6, 11, 15, 17, 18, 19, 20
Pg 68 read it
Pg 69:
1, 3, 4
1.
What is the element in the halogen
group and 3rd period?
Chlorine
2. What element is a rare earth metal and
has an atomic mass of 237?
Neptunium
3. What transition metal is in group IIB and
period 6?
Mercury
4. What is the group name of the
element in group VIA and period 6?
Metalloids
1.
2.
3.
4.
5.
6.
Give 2 evidences that a chemical change is
happening.
Give 2 examples of a chemical change.
How many total electrons are in an atom of
bromine?
How many valence electrons are there in an atom
of bromine?
`Is bromine a metal, a non-metal or a metalloid?
Chromatography is a method of separating the
components in a __________ based on their
solubility in a solvent.
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Define matter
KMT (kinetic molecular theory of matter)
Phases of matter (4 main ones)`
Difference between :
Atom and molecule
Element, compound and a mixture
Homogeneous and heterogeneous mixtures
Physical and chemical properties
Physical and chemical changes
Extensive and intensive physical properties
Amorphous and crystalline
Evidence of a chemical changes (things you can
observe)
What are “physical means”
1.
2.
3.
4.
5.
Which of these is a physical property?
A) flammability B) volatility C) toxicity
Which of these is an extensive physical property?
A) density B) volume C) mp D) color
What methods could you use to separate out most of the
components in this mixture:
ocean water (sandy salt water)
The KMT (kinetic molecular theory of matter states that all matter
is made of tiny ______ and these are in constant ______.
Which of these processes requires the constant addition of heat?
A) freezing B) burning paper C) sublimation
D) condensation E) cooling a soft drink

http://www.kentchemistry.com/links/Matter
/HeatingCurve.htm
1 atm
RT 25.0
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https://www.youtube.com/watch?v=66bCUG0eKrkhttps://ww
w.youtube.com/watch?v=66bCUG0eKrk Supercritical fluids
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https://www.youtube.com/watch?v=thnDxF
dkzZs Crash Course Hank Atomic History
10 min
https://www.youtube.com/watch?v=GhAn8x
ZQ-d8 Bozeman The Atom AP Physics 6 min
https://www.youtube.com/watch?v=accyCU
zasa0 Bozeman Quantum model 5 min
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https://www.youtube.com/watch?v=rcKilE9
CdaA Crash course Electrons 12 min
https://www.youtube.com/watch?v=O1WpE
5ntqbQ Big Bang Sheldon electrons at 2:43
http://chemistry.about.com/od/chemistry101/a
/learnchemistry.htm Teach yourself Chemistry

https://www.youtube.com/watch?v=njGz69B
_pUg Bozeman The Atom 9 min
1.
2.
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http://www.sciencegeek.net/APchemistry/APtater
s/PhaseDiagrams.htm Phase diagram quiz
http://c2w.com/quizzes/109048-ATOM-BASICSQUIZ Atom basics quiz
http://www.softschools.com/quizzes/chemistry/at
omic_heory/quiz666.html Quiz atomic models 1
http://www.softschools.com/quizzes/chemistry/ea
rly_models_of_the_atom/quiz672.html Quiz atomic
models 2
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BIG Quiz on Monday! Over what?.......
Atom basics-- [subatomic particles (relative
size, charge, location), quarks, calc # of SP,
isotopes, writing an isotope symbol, ions
(cations lost e, anions gained), ]
Matter in general-- (see slide 60)
Theories of atomic structure --what did each
think about what the atom looked like:
(Democritus, Dalton, Thomson, Rutherford,
Bohr, Chadwick)
Heating curves and Phase diagrams– be able to
label and interpret
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Bell ringer will be graded
Over…. atom basics
Bohr model
Atomic models (Dalton, Thomson, Rutherford,
Bohr)
Matter
Part
2
Electron
configurations….