Bell Work 9/30/14
 Pick
up your graded papers.
 Tape them in your notebook.
 See my notebook as the example.
 We will have another notebook
check in the near future.
Stations Instructions

You will need your paper and a writing utensil.

You MUST work with the group assigned to you!

Read the information at each station, complete instructions,
and fill in your notes.

When everyone is done, we will watch the videos as a group.

Take your lab papers home and fill in the Summary Sheet for
Homework.

There will be a quiz tomorrow on all of the scientists, their
theory, experiment, model and conclusion.
The first group will immediately proceed to
Station #1 while the others tape papers in
notebook. When Group #1 moves to Station
#2, the next group will go to Station #1, etc.
Lab Groups
1. Phanessa,Trey, and Clarissa
2. Steven, Dawson, and Jayme
3. Zane,Victoria, and Courtney
4. Joyce, Alexis, Daniela, and Kierstin
5. Marye’, Brandon, and Mary
6. Kievie, Tori, and Joanna
John Dalton
Station 1
Read all of the following:
John Dalton

The Greek philosophers were the first to discuss the possibility that matter may be made up of
small particles. They came up with the concept of the atom being the smallest particle that
could not be divided, created, or destroyed. Without any scientific measuring tools or
equipment to conduct experiments, the concept of the atom was simply an idea and not a true
scientific theory.

Two thousand years later, an English school teacher named John Dalton who liked to study
meteorology (the study of weather) in his spare time, performed experiments with different
gases under controlled conditions and took careful measurements and observations.
His Experiment:

Dalton observed various chemical reactions and determined how they reacted and recombined
to form new substances. He said that there were many different “flavors” or kinds of atoms. To
keep track of them he gave each element its own picture and when it combined into a new
substance it had its own independent picture too (Figure 2).

His Theory: Dalton’s Postulate (also called Dalton’s Atomic Theory)

All elements are composed of tiny indivisible solid particles called atoms

Atoms of the same element share the same mass and properties.

Atoms of different elements have different masses and properties.

Atoms are not created, destroyed, or converted into different elements. They can
only be rearranged to make new compounds

Atoms join together in whole number ratios to form compounds
Ex: H2O or water is always found in a 2:1 ratio
This means that there are 2 Hydrogen Atoms for every 1 Oxygen Atom
Answer the questions on your worksheet before moving to Station 2
Station 2
Read all of the following:

1.
2.
3.
4.
5.
6.
7.
8.
9.

John Dalton’s Model of the Atom
Collect one bag from your teacher.
Give your lab partner one of the Gobstoppers® then take the other for your self.
Place the Gobstopper® on your tongue in your mouth.
Does the Gobstopper® take the shape of your mouth? (Record your answer)
Does it turn into a liquid? (Record your answer)
Can you make the Gobstopper® flat? (Record your answer)
Which state of matter is your Gobstopper®? (Record your answer)
Is it solid throughout? (Record your answer)
Look at the model hanging at your station.
This solid sphere, just like a Gobstopper®, represents Dalton’s theory of the atom.
He believed that the atom was a solid sphere of identical particles.

Draw a picture of Dalton’s Model of the Atom on your WKST
Answer the questions on your worksheet before moving to Station 3
Station 3
Read all of the following:

Dalton’s Conclusion

While Dalton’s Postulates seemed valid at the time, we have learned that his theory
can be proven wrong. We know today that …

An atom can be further divided into protons, neutrons and electrons.



Atoms of the same elements vary in their masses and densities because isotopes exist!

Isotopes are atoms of the same element, but have different numbers of neutrons

(Disproves his second postulate)
Argon and Calcium Atoms each have an atomic mass of 40



(Disproves his first postulate)
(Disproves his third postulate)
Some identical elements exist with different properties

Example: charcoal, graphite and diamond are all made up of carbon, but each has its own unique set or properties

(Disproves his third postulate)
Not all elements combine in simple whole number ratios to form compounds

Example is sugar, C12H22O22

(Disproves his fifth postulate)
Answer the questions on your worksheet before moving to Station 4
J. J. Thomson
Station 4
Read all of the following:

J. J. Thomson

J.J. Thomson was a British physicist who studied charged particles in gases. He is credited with the
discovery of the electron as a result of his Cathode Ray Experiment.

An electron is a negatively charged, fast moving particle.

His Experiment – The Cathode Ray Experiment

His experiment measured the effects of both magnetic and electric fields on a cathode ray. Because
of this, he was able to determine the charge-to-mass ratio of the charged particle, the electron. He
said that there were particles smaller than the atom, disproving Dalton’s First Postulate!

Using your latitude either scan the QR code here:
Or go to: http://brammellchemistry.weebly.com/scientists-video-1.html

Watch the video on your tablet
Answer the questions on your worksheet before moving to Station 5
Station 5
Read all of the following:

J. J. Thomson’s Model of the Atom

Thomson used his experiment’s results and said that an atom was made up of a
positively charged substance with negatively charged electrons scattered
throughout. His model came to be known as the “Plum Pudding Model” or cookie
dough.
1.
Look at the model at your station.
2.
What color are the electrons?
3.
What color is the positively charged substance material?
4.
Pick up a sample of plum pudding at your station. You may eat this 
5.
What do the raisins represent in your plum pudding? (Record your answer)
6.
What did the yellow pudding represent in your plum pudding? (Record your answer)

(Record your answer)
(Record your answer)
Draw a picture of J.J. Thomson’s Model of the Atom on your WKST
Answer the questions on your worksheet before moving to Station 6
Station 6
Read all of the following:

J. J. Thomson’s Conclusion

He had identified the first subatomic particle – the electron.

He received a Nobel Prize in 1906 for this discovery.

He disproved Dalton’s First Postulate that all atoms are composed of tiny indivisible
solid particles called atoms.

Thomson’s theory did not account for where electrons, protons and neutrons live
so we will learn why and how it is proven wrong next.
Answer the questions on your worksheet before moving to Station 7
Ernest Rutherford
Station 7
Read all of the following:

Ernest Rutherford

Ernest Rutherford was a student of J.J. Thomson and did some tests on his plum pudding model. He
wanted to study how positively charged alpha particles interacted with solid matter. His research led to
his discovery of the nucleus.

A nucleus is the extremely small, positively charged, dense center of an atom that contains both neutrons and
protons.

A proton is a subatomic particle carrying a positive charge of +1.

His Experiment – The Gold Foil Experiment

In his experiment, a narrow beam of alpha particles was aimed at a thin sheet of gold foil. When an
alpha particle hit this gold foil it produced a flash of light. By tracking where the flashes occurred, the
scientists could determine if the atoms in the gold foil deflected the alpha particles.

Using your latitude either scan the QR code here:
Or go to http://brammellchemistry.weebly.com/scientists-video-2.html

Watch the video on your tablet
Read all of the following:

His Experiment – The Gold Foil Experiment
1.
Using a highlighter, mark where most of the alpha particles hit.
2.
Why did most of the particles pass through the gold foil?
3.
What was the unexpected observation from his experiment?
4.
Using the other highlighter, mark where the unexpected deflections hit on the picture.
Answer the questions on your worksheet before moving to Station 8
Station 8
Read all of the following:

Ernest Rutherford’s Model of the Atom

Earnest Rutherford’s experiment led to his theory of the atom. A few of the alpha particles were
deflected at large angles. Several particles were deflected straight back toward the source. He
said that this experiment did not agree with the Plum Pudding Model. He believed that there
was a small, densely packed nucleus of positive charge in the center of the atom. He theorized
that empty space with scattered electrons were around the nucleus.
1.
Look at the model of his atom at your station. Read each question and record your answers on your
worksheet
2.
The ball in the center is representing the ___________________.
3.
The nucleus is
4.
There is lots of empty _______________ in the atom.
5.
Draw a picture of Rutherford’s Model on your worksheet
small
medium
large
in comparison to the atom.
Label the nucleus with either a positive (+) or negative (-) charge
Answer the questions on your worksheet before moving to Station 9
Station 9
Read all of the following:

Ernest Rutherford’s Conclusion

He received the Nobel Prize in Chemistry in 1908, he was made a knight and is even
buried in Westminster Abbey. He is responsible for the discovery of the nucleus,
where the protons lives. He said that most of the atom is made up of empty space.
His experimental results from the Gold Foil Experiment disproved J.J. Thomson’s
theory of an atom.

Next we will learn that Rutherford’s theory did not account for other subatomic
particles.
Answer the questions on your worksheet before moving to Station 10
Neils Bohr
Station 10
Read all of the following:

Neils Bohr

Neils Bohr was a physicist who studied with J.J. Thomson and later with Ernest Rutherford. He
said that he didn’t think Rutherford’s model was right to explain an atom because it would be
unstable. He believed that electrons couldn’t exist as Rutherford had explained.

His Experiment -

His experiment was based on a quantum model where the electrons jump between energy
levels or orbits. He used an experiment with the hydrogen atom to explain and support his
theory of an atom. This experiment revealed a line spectrum just for the element hydrogen.
Answer the questions on your worksheet before moving to Station 11
Station 11
Read all of the following:

Neils Bohr’s Model of the Atom

He built a simple model of an atom where the electrons orbit (in circular
paths) around the nucleus. The nucleus is home to both protons and
neutrons.


A neutron is a neutral subatomic particle that has mass.
The electrons travel inside an atom on a particular path with a fixed
energy.


They live on an energy level.
Called the Planetary System (like our solar system)
Station 11
Read all of the following:

Neils Bohr’s Model of the Atom
Planetary System
Bohr’s Model
Electrons are like our planets
Electrons live on energy levels
Nucleus is like our sun
Nucleus is full of protons and neutrons
Answer the questions on your worksheet before moving to Station 12
Station 12
Read all of the following:

Neils Bohr’s Conclusion

Bohr’s theory of the atom explained his experiments results for hydrogen correctly. He
disproved Rutherford’s theory by the nucleus being home to both neutrons and protons. He
also said that electrons lived on energy levels inside the atom.

Today we know that Bohr’s model was accurate for the nucleus, but flawed for the electrons.
We know that electrons do not move around the nucleus in circular orbits and we follow
what is called the Quantum Mechanical Model of the Atom.