Transcript Atomic Theory

Atomic Theory
History of the Discoveries Related to the Atom
Mrs. Paul
Main Contributors To Atomic Theory
450 BC
Democritus:
Matter made
of tiny
things called
ATOMS
1924
Debroglie:
Matter has a
wave-like
nature
1800
Dalton:
Wrote an
Atomic
Theory with
4 main
ideas
1926
Schrödinger:
E- travel in
waves
1897
Thompson
negative
charge in
the atom
1901
Planck:
Quanta,
predictable
packets of
energy
1910
Millikan:
Charge on
the electron
of -1
1926
1932
Heisenberg:
E- are waves
and particles
Chadwick:
neutrons
1911
1913
Rutherford:
atoms have
a nucleus
Bohr:
Proposed a
model of an
atom
1962
Gell-Mann:
Quarks
Timeline of Atomic Theory
450 BC
1800’s
_________________________________________________________
Democritus:
matter was made of
“atoms”
Dalton:
proposed 4
components to an
Atomic Theory.
Dalton’s Theory: Foundation of
Future Investigations
• All matter consists of tiny particles.
• Atoms are indestructible and
unchangeable (Has been modified
with recent discoveries in nuclear
chemistry)
• Elements are characterized by the
mass of their atoms.
• When elements react, their atoms
combine in simple, whole-number
ratios. Their atoms sometimes
combine in more than one simple,
whole-number ratio.
Click the picture to explore
more about experiments
related to Dalton’s theory.
Atomic Theory 1897-1962
Sub-Atomic Particles
___1897________ 1910________ 1911_________1913________1932________1962___
Thomson
Millikan
Rutherford
Bohr
Cathode Ray
Experiment
Chadwick
Oil Drop
Experiment
Gold Foil
Experiment
Bohr Model
Gell-Mann
History of
Chadwick
What are p+ and
n0?
Neutron
Quarks
Negative Charge on
charge in
e- is 1the atom
Alpha Particles
and Nucleus
Animation
Nucleus
Bohr’s
Discovery
Quantum
Model
3 Basic Parts of the Atom.
Click on this link and participate in the interactive questions
Types of Quarks Determine Charge
http://nobelprize.org/educational_games/physics/matter/1.html
Quarks = up (+2/3) and down (-1/3)
p+ = 2ups and 1 down
+2
3
+2
3
-1 =
3
+1
n0 = 2 down and 1 up
-1
3
-1
3
+2 = 0
3
Gluon forces
between
quarks
Energy Nature of Matter
1900-1926
____________1905______1924_____1926______1926__
1900
Planck
Quantum
Hypothesis
Atoms Absorb and
Emit Light
Photo Electric
Animation
Quanta
Einstein
Matter and Energy
different forms of
the same thing
E=mc2 Explained
E=mc2
De Broglie
Wave
nature of
matter
Schrodinger
Heisenberg
e- orbits as a
wave
Uncertainty
e- acts as a
wave and a
particle
Electrons……..
Are they a particle or a wave?
Electrons travel in waves
Click this link for explanation
Electrons as Waves
Electrons travel in discreet packets called photons which
travel in waves.
• To describe these unique packets or quantities of
energy the term “quanta” is used.
• Every element on the periodic table is made up of atoms
with a unique signature of spectral lines. Click the picture below
Electron behavior as it moves
to other energy levels.
• This emitted energy is
equal to the difference
between the high and
low energy levels, and
may be seen as light.
Click the picture for animation
Electrons as a Particle having
position in an Atom
• Electrons are particles with a charge of 1- , it has mass, and
its position can be predicted with reliability.
Bohr proposed 4 characteristics to predict the position of an
electron.
l = the distance from the nucleus
m = the shape of the orbital in which the e- occupies. (s,p,d,f)
n = axis the orbital occupies. (x, y, z)
s =spin of the e- (+1/2 , -1/2)
1. Distance from the nucleus
• Levels 1-7: When looking at the periodic
table, can be determined by the period
Elementary Connections
number.
1
2
3
4
5
6
7
2. Shape of the Orbital
3. On the x,y,z Axis
The # of electrons in a particular region determines the shape.
s shape 2e-
p shape 6 e-
f shape 14 e-
d shape 10 e-
Atom with overlapping orbitals
4. Spin of the Electron
Electrons exhibit particle and wave
like behavior called “Duality”
Click here for animation
Einstein vs Bohr
Einstein: causality
If you know all the
initial conditions of
your system and you
know the laws of
physics, you can figure
out exactly what’s
going to happen
Bohr: Predictability
If you know the
initial
conditions and
you know the
laws of
physics, you
can figure out
the probability
of various
outcomes
happening, but
you can never
know which
one will
definitely occur
until after it’s
over.
Particles of the Atom to date:
• Nucleus
– Protons = p+ = 3 quarks
– Neutrons= n0 = 3 quarks Held together by
a force called :
• Electron Cloud
Gluon
– Electrons =e- (particle/wave)
•
•
•
•
http://www.youtube.com/watch?v=ol_FrffMoQ8
http://www.youtube.com/watch?v=45KGS1Ro-sc
http://www.youtube.com/watch?v=fm7oGOdsaQk
http://www.teachersdomain.org/asset/lsps07_vid_stability/