Honors Chemistry I            Quantum Atom                  Name

                                                                                                  Number

 

Answer the following questions using the web site:

 

http://colorado.edu/physics/2000/quantumzone/index.html

 Go to the Table of Contents tab on the bottom of the page.  Scroll down to find

Science Trek.  Click on Electromagnetic Waves

 

ELECTROMAGNETIC WAVES

 

  1. What are electromagnetic waves?

 

  1. A wavy disturbance that repeats itself over a distance called the __________.

 

  1. What is the range of wavelengths of radioTV waves?           Microwave?   

 

  1. millimeter?               Infared?             Visible?              Ultraviolet?

 

  1. x-rays?                     Gamma rays?

 

So what's the wave made of?  The wave, or "disturbance," is in an invisible thing called the ______ _______ _______.  To understand electric forces, we have to learn something about charged particles like ________ ______ ____________

 

Click on Next

THE ELECTRIC FORCE

 

  1. To understand electric fields and electromagnetic waves, you need to know how _________ (such as "negative" _________   and "positive" _________ cause each other to move.
    Click the mouse anywhere in the box.

 

  1. What happened?

 

  1. That's because the positive charge exerts an invisible, attractive force on the electron -- an __________ ____________

 

  1. Now see what happens when you give the electron a little "throw" as you set it down. To do this, click-drag the mouse in any direction.  What happens?

 

  1.  Try to get four electrons circling the nucleus, then click on the show force button.

Click on Next

ELECTRIC FORCE FIELDS

 

  1. In physics, a force field is ________________________________

 

  1.  Instead of talking about the force a positive (+) charge exerts on an electron, we can say the __________creates a force "field" in the empty space around it. An electron put down at any place in this force field is pulled towards the _________ charge; a positive charge set down at the same place is ___________ away.

 

  1. Try putting down "test" electrons with the mouse to see which way the field points and how strong it is; the line points in the direction in which the electron will ________, and the length of the line tells you the __________ of the force at its current location.

Click on the New force Field applet.

Notice the direction of the arrow as the positive or negative poles are moved.

Click on back

Click on next

VIBRATING CHARGES AND ELECTROMAGNETIC  WAVES

 

Use your mouse to drag the negative charge up or down, then let it go to start it oscillating.
Use the slider to adjust spring tension.

 

Click on Quantum Atom:

 

SPECTRAL LINES

 

  1. When sunlight shines through a prism, what happens? Why?

 

 

  1. But when scientists looked at the light coming off of just one element, hydrogen for instance, they___________________________-. Instead they just got _________________________.

 

 

  1. That would mean that the atoms were only ______________________

 

 

  1. Do all atoms create the same colors?

 

.The colored lines _____________ are a kind of "signature" for the atoms.

 

  1. If you put light from a common streetlamp through a prism, or look at the light through a diffraction grating, you will see distinct lines. Two common kinds of street lights use ___________ and __________ bulbs. Each of these lights has a different spectral "signature", and you can tell what kind of lamp it is by its spectral lines.

 

 

19.  How many spectral lines are visible for helium?       What colors?

      Lithium?        What colors?

      Carbon?        What colors?

 

20. Spectroscopy is the

 

21. To explain the spectral line puzzle, _________came up with a radical model of the atom which had electrons orbiting around a nucleus.

Click on Next

 

BOHR ATOM

 

22. Bohr came up with an extraordinary rule the electrons had to follow: Electrons can only be in "___________” orbits.

 

23. They could "_______" between these special orbits, however, and when they jumped they would wiggle a little bit.

 

24. To see this happening, try clicking on different orbits in the model of an atom below. Those squiggles are little bursts of light (_____________). We call them __________.

25. It said that energy could only change in little jumps. These are called ________ and that's why this kind of physics is called ______________.

26. The important part is that these jumps cannot be broken down into smaller steps. For an electron on the move ___________________________.

Click on Next

ENERGY LEVELS

27. We're going to think about electrons being in special ___________ ________.   We just use this rule: ____________________________

28. It turns out that electrons don't really move in little ___________ orbits. We can take a little detour to see how the Schrödinger Atom more accurately depicts what is happening inside atoms.

click on Schrodinger Atom

SCHRODINGER ATOM

29. A physicist named ___________________ showed that electrons are really waves that...
 Hold it! What do you mean electrons are waves?! I thought they were particles!


30.If you perform an experiment to see where a ________ is, then you find something particle-like. But otherwise it's a _______that carries information about where the electron probably is.

31. For some energy levels, if you check position enough times you may see an "orbit-like" pattern, but don't be fooled into thinking that electrons are actually moving around in little circles.
32.They may be misleading about _________ the electron is, but they do tell us how much _________ it has.


33. We call this the _______ ________ of the electron. Because the idea of orbits is so misleading, physicists started using a picture of the atom which just showed energy levels as relative heights.

And we call this the "_______________ _______," of course.

 

 Read Two-Slit Experiment. Click on back

31.     Until you check where it is, it's really just a ________. Not only that, but Schrödinger showed that these electrons don't even move. The waves are ________________. Each time you check where an electron is you will find it in a different place, but that doesn't mean it's moving in between checks. For some energy levels, if you check position enough times you may see an "orbit-like" pattern, but don't be fooled into thinking that electrons are actually moving around in little circles.

Click on the orbits to change energy levels.

Click on next

ATOMIC SPECTRA

 

32.     an important thing to realize is that transitions between the same energy levels always produce the same ________ photon. (Actually, photons don't have colors but often that is a convenient way of thinking about their wavelength or frequency.)

Click on an orbit to make the electron jump energy levels.

33.     Each time the electron jumps  ___________a level it produces a photon, and the same jumps produce the same colors.

37. When you have a whole lot of atoms, I'll bet you get all these ________lines appearing at once.

38 Exactly, and that's what scientists mean by ___________. By the way, the converse is true, too. Those same color photons are the only ones that will bump the electron up to higher levels. Photons of other frequency will pass right through the atom.

39. That would mean atoms are kind of "_____________” to all light except their own "team colors."

40. We keep talking about the "color" of these photons. Does that mean that atoms only interact with visible light? What about other kinds of electromagnetic radiation?

            CLICK ON TABLE OF CONTENTS.  SCROLL DOWN TO ELEMENTS AS ATOMS.  CLICK ON BEYOND THE HYDROGEN ATOM

Let me show you an interactive periodic table of elements, which goes up to number 36, krypton (Kr).  CLICK ON THE PERIODIC TABLE.  WHEN IT OPENS CLICK ON THE DIFFERENT ELEMENTS.