Transcript day3-ruth, mill, chad, subpart

Do Now
Work silently. Raise hand to ask Ms.
Hughes anything.
1. Describe Thomson’s atomic model.
2. Describe Dalton’s atomic model.
Announcements
• Unit 3 test next Friday
• If you have not taken 2 chemistry tests yet
this semester, see me after to arrange a
make up
• Also, come in for quick tutoring, then
RETAKE GLEs for a GRADE BOOST
Mystery Element
#1: Too little of this element in
the body causes osteoporosis.
#2: You can get this element
from drinking milk
#3: It is good for your bones!
Numero Cinco! - R. A.
Millikan
• Experiment:
Millikan Oil Drop
Experiment
• When: 1909
• Where: U.S.A!!!!
Millikan’s Oil Drop Experiment
Millikan!
• Sprayed oil drops
• Drops fell between magnetic plates
• Drops radiated to give them negative
charge
• Measured how fast they fell to find charge
and mass
• Gravity pulls them down…But since
opposite charges attract and likes repel
• The magnetic plates pushed the drops up
Millikan’s Calculations – Whoa!
What were Millikan’s
conclusions?
I have most
accurately
measured the
charge of an
electron:
-1.59 x 10-19
Coulombs
What were Millikan’s
conclusions?
I have also most
accurately
measured the
mass of an
electron:
9.109 x 10-31kg
What were Millikan’s
conclusions?
The electron
is really
really small
and has a
negative
charge
Numero Seis! - Ernest
Rutherford
• Experiment: Gold
Foil Experiment
• When: 1910
• Where: Montreal
Gold Foil Experiment Explained
• Alpha helium particles were shot through a
piece of gold foil
– Think aluminum foil but thinner and made
out of gold!
• Alpha helium particles are 8000 times more
massive (bigger) than electrons
• Rutherford thought alpha particles would
knock electrons out of the way, since atom is
only electrons in sea of positive charge
http://micro.magnet.fsu.edu/electromag/java/rutherford/
Remember! This is the current
model of the atom (Thanks to
Thomson)
More History
Ernie’s (Rutherford) Big Adventure
Thin Sheet of Gold
Atoms
What were Rutherford’s
conclusions?
• Pretend you are Rutherford
• As Rutherford, what
conclusion would you make
based on the data from the
Gold
Foil
Experiment?
Hint: Positive repels
=
positive, negative
repels negative
-
+
-
-
-
What were Rutherford’s conclusions?
•Discovered the nucleus, a
concentrated mass with
positive protons!
•Nucleus is in the center of
the atom
•The atom is mostly empty
space
•Electrons orbit around
nucleus
What’s this empty space idea?
• The atom is mostly empty
space!
• The nucleus is TINY
compared to the size of
the entire atom!
• Called “the planetary
model” because electrons
orbit like planets in empty
space
Relative Size of Nucleus to the Atom
Rutherford Simulation
• Let’s do this thing OURSELVES…but
without radioactive particles
James Chadwick
• Experiment:
Beryllium Foil
Experiment
• When: 1932
• Where:
Cambridge
(England)
Beryllium foil experiment
•
•
•
•
Similar to gold foil experiment
Shot alpha particles at beryllium foil
Noticed neutral radiation coming out
That neutral radiation could knock protons
out of the way
• Therefore, heavy neutral particles exist in
the atom
What were Chadwick’s
conclusions?
Neutral radiation
emitted; therefore, the
nucleus contains another
subatomic particle
called the neutron (has
a neutral charge)
PROTON
NUCLEUS
-
-
+
-
+
-
ELECTRON
-
+
+
-
-
-
NEUTRON
Picture History
Draw a picture history of the atomic
model on the timeline
RAFT - Independent Work Time
Due Friday
R = Role
Pretend to be either Dalton, Thomson, Rutherford.
A = Audience
You are writing to the theorist directly before you.
F = Format
Newspaper article, Letter or Rap
T = Topic
Details of your discovery, how you know it is true,
and why it is better than the guy before you.
YOU HAVE “WORKED” HARD…DEFEND YOUR
RESEARCH!
Assignment: RAFT
• Option 1: Rap
• Role: An atomic Theorist
• Audience: Writing to another atomic
theorist
• Form: an appropriate rap
• Topic: Why your theory and model is better
than theirs
+3 points for presenting on Friday
Assignment: RAFT
• Option 2: Polite, Formal Letter or
Newspaper article
• Role: An atomic Theorist
• Audience: Writing to another atomic
theorist
• Form: a formal letter
• Topic: Politely stating why your theory and
model proves theirs wrong
+3 points for presenting on Friday
Assignment: RAFT
Things to Include
• Personal information about both theorists where they’re from, physical appearance,
etc.
• All necessary facts about both theories or
models
• How the theory is better than the one that
came before it
3 Subatomic Particles
• Protons
• Neutrons
• Electrons
THE PROTON
• Fat
(heavy)
+
p
• Positive 
(charge)
• Doesn’t move
(lazy)
THE NEUTRON

°
N
• Fat
(heavy)
• Neutral 
(charge)
• Doesn’t move
(lazy)
THE ELECTRON
• Skinny
(very light)
e
• Negative 
(charge)
• Moves a lot
(runs around)
Review of Subatomic Particles
Subatomic
Particle
Protons
Neutrons
Electrons
Location
Mass
Charge
NUCLEUS
1.6726 x 10-27 kg
1+
NUCLEUS
1.6749 x 10-27 kg
NEUTRAL
OUTSIDE
NUCLEUS
9.1094 x 10-31 kg
1-
Review: Subatomic
Particles
+
P

e-
N
Exit Slip
1. What experiment did Rutherford use to?
What did he discover?
2. How did Rutherford change the atomic
model?
• Hw: Make it a QUALITY short answer
– What are the three subatomic particles and
how did we discover each? Name the
experiment and give a brief description.
•
Top ten: how’d we do?