Good Morning!Starter: What does an atom look like?Today we will…Check the starter questionsWhat do you know about the Atom?• Goal:
– determine what you do and do not know about atoms
– think about why you believe what you believe
– Gain some understanding on how we came to our current thinking on the atom.
What is an atom?
Why do you believe that they exist and everything is made out
of them?
Tear off a piece of paper and rip it in half.
• Now tear it in half again• Now again• Will there come a time where you can’t rip it
in half?• Let’s say you had a shrink ray and could
make yourself smaller so the size of your hands was not an issue.
• Could you then?• Numbers can be “cut” in half forever, why
not paper?
We are not the first to struggle with this concept
• In ancient Greece (400 B.C) a man named Democritus came up with the idea that you will eventually come to a point where you can no longer cut an object in half
• He said you would come to an “uncuttable” object.
• Brain Pop
A choice
• I am about to hand out a worksheet
• You can either work on it by yourself and receive 15/15 if you complete it. Or you can watch a video and powerpoint and get 12/15 if you complete it.
• The choice is yours
• Brain Pop
Good Afternoon
• Today we will continue our work on the history of the atomic Model
• Starter: Why would the discovery of the electron force us to change our understanding of the atom?
• Goal: Understand the Bohr Model of the atom and how we arrived at the Modern Model.
Atomic Theory and Models
Dalton thought that
• atoms were like smooth, hard spheres that could not be broken into smaller pieces.
• All atoms of an element were identical
• An atom of one element can not be changed into an atom of a different element.
Atomic Theory and Models
• Thomson suggested that atoms had negatively charged electrons embedded in a positive sphere.
Rutherford found that most particles went through proving that atoms (and everything made of them) are mostly empty space.
• Rutherford was surprised that a few particles were deflected strongly. This led him to propose an atomic model with a positively charged nucleus.
Close
up of
What
Happened
inside the
gold foil.
Atomic Theory and Models
• Rutherford’s model looked like what you see here with a positively charged nucleus.
• Bohr figured out that there are levels and developed the Bohr Model
• We coupled this with knowledge that you can’t predict where the electrons will be.
• Chadwick’s discovery of the Neutron lead to a reengineering of the nucleus.
A Brain Pop Quiz
• Brain Pop
Models of Atoms• A summary of visuals
Video
Want to build an atom?
• Atom builder one
• Atom builder two
