Summary:

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Learning Goals / Objectives:

• To understand basic composition and structure of the atom
• To understand subatomic particles, their charges and relative masses
• To understand which particles comprise the mass of an atom, which comprise the volume
• To understand what determines the “identity” of an element
• To understand ions and isotopes.
• To understand the concept of electron “clouds”.
• To understand simple bonding concepts.

Background

Preparation
If not already prepared in advanced, velcro should be applied to points between shells to hold them together. Velcro should also be applied to complete poof balls to form “bonds” with another atomic model. The model should be completely taken apart to begin this activity.

Anticipatory Set:

1. What are atoms and why are they important to everyone?
2. What determines the identity of an element?
3. What makes up most of the mass of the atom? The volume?
3. What is an isotope? How is an isotope different from its “parent” atom
4. How is an ion different from its “parent” atom?
5. What are electron clouds? Are they solid and well-defined or soft and squishy?

Instructions / Activities:

A. The Nucleus

1. Obtain at least ten (10) magnetic beads of each color. Designate one color as the protons, the other color as the neutrons.
2. Put two beads of each color together. This is a helium nucleus.
3. Make a carbon nucleus by putting the correct number of beads of each color together.
4. Make an oxygen nucleus now.
5. Now make an isotope: deuterium is made by putting one proton bead together with one neutron bead. Tritium is similar and is made by putting one proton bead together with two neutron beads.
6. Carbon 13 is a well-known and highly used isotope. Now make this isotope by putting together the correct number of proton and neutron beads.
7. Now try to make an isotope of nitrogen 15.

B. Electron Clouds

1. To complete our atoms, we need to include the electron clouds, which represent the volume in which one is likely to find the electrons. A hydrogen atom, the simplest atom, has only one proton in its nucleus, so pick out a proton bead. Place the two halves of one small foam shell around this bead. This represents the “1s” electron shell, which contains hydrogen’s one electron. You have now made a hydrogen atom.
2. Make an oxygen nucleus as you did in Part A. This atom has two electron shells, which contain a total of 8 electrons. Place two shells around this nucleus. You’ve now made an oxygen atom.
3. Notice the “squishiness” of the electron clouds. Are larger clouds more or less squishy than smaller ones? (We will discuss this in class, how and/or whether this connects to reality.)

C. Simple bonding and molecules (May be omitted if time is an issue.)

1. When two or more atoms share electrons, they bond to form a molecule. One very common and important molecule is the oxygen we breathe which consists of two oxygen atoms. Get two oxygen atoms and “bond” them together with the Velcro.
2. Water consists of two hydrogen atoms and one oxygen atom. The two hydrogen atoms bond to the oxygen atom at an angle of about 110 degrees. Get two hydrogen atoms and an oxygen atom and bond them at an angle using the Velcro.
3. Make any other molecules you’re familiar with, given enough “atoms.” (Pool resources with other groups!)

Assessment:

1. What happens to an atom if you change the number of protons it contains? For example, what happens if you add 1 proton to a gold atom?
2. What happens to an atom if you change the number of neutrons it contains? For example, what happens if you add 1 neutron to a gold atom?
3. What happens to an atom if you change the number of electrons it contains? For example, what happens if you remove an electron from a gold atom?
4. What subatomic particle designates or distinguishes an element from other elements?
5. What subatomic particle(s) constitute the mass of an atom? What constitutes the volume?
6. In a Fluorine 19 isotope, how many protons are there? How many neutrons?
7. How does an isotope differ from its parent element?
8. How does an ion differ from its parent element?

9. How many electron shells does a helium atom have? How many does a nitrogen atom
have? Which do you think is more “squishy”? Why do you think this is?
10. Draw a picture of your water molecule that you made. Make sure to clearly indicate
relative sizes and the appropriate bond angle.

Wrap-up / Closure:

Reflections: For your Science Journal

1. Does this activity clearly and easily demonstrate the identified standard? If not, how would you change the activity so that it better illustrates the standards?
2. What prior knowledge must your students have before completing this activity?
3. Would you feel comfortable and safe enough letting your students do all the parts of this activity? If not, what would you cut out? Would you do those parts as demonstrations?
4. How could you alter the parts using heat to make them more safe for students? Suggest some modifications to make this more “kid friendly.”
5. Any modifications or changes needed to the “learning objectives”, “questions to investigate”, or “analysis” sections of the activity?

Attachments:

These materials are contained in a kit in our Library!