Construct an Atom Model

What you need:

• pipe cleaners
• crafting beads
• fuzzy pom-poms
• glue dots 
  
  

Instructions:

1.  Have students pick an element from the first two rows of the Periodic Table of Elements. 

2.  Students should research their element to determine the chemical symbol, atomic number, and  atomic weight.  Here we will be building a carbon atom.

Element: Carbon

Chemical Symbol: C

Atomic Number: 6

Atomic Weight: 12.01

3.  Students will then calculate the number of protons, neutrons and electrons that make up the element they have chosen.

The atomic number is equal to the number of protons and electrons in the nucleus of an atom, and determines which element the atom is.  For example,  any atom that contains exactly six protons in it's nucleus is a carbon atom.  The atomic weight (relative atomic mass) of an element is the ratio of the average mass of atoms of the element to 1/12 of the mass of an atom carbon-12 (unified atomic mass unit).  Confusing? Lets simplify it.  To calculate the number of neutrons in an atom's nucleus you need the element's mass number.  You can determine this by rounding the atomic weight to the nearest whole number.  In carbon's case, we round 12.01 to the whole number 12.  We can now say:

Mass number = number of protons + number of neutrons

For carbon, the equation becomes:

12 = 6 + number of neutrons------> 12 - 6 = number of neutrons

Solving for the number of neutrons you should get six neutrons!

Carbon

Number of protons: 6

Number of electrons: 6

Number of neutrons: 6

3.  After you have determined the number of protons, neutrons and electrons it is time to distribute the electrons in it's shells. An electron shell can be thought of as an orbit followed by electrons around an atom nucleus.  Each shell can only contain a fixed number of electrons, this is referred to as electron capacity.  The maximum number of electrons that can occupy a specific energy level can be found using the following equation:

Electron Capacity = 2n^2

*the variable n represents the Principal Quantum Number, the number of the energy level in question.

** ^2 signifies to the second power or squared.

In carbon's case there are six electrons.  The first shell's capacity is two, therefore only two of carbon's six electrons are found in the first shell. That leaves four electrons to fit comfortably in the second shell.

4.  Finally, we can start building an atom!!!! Begin by taking one pipe cleaner and making a loop at the top.  This will enable you to hang you atom when it is completed.

5.  Count out enough pom-poms for the number of protons and neutrons in the nucleus of your atom.  For the carbon atom I counted out 6 protons and 6 neutrons.

6.  Use the glue dots to piece together the nucleus of the atom.

7.   Affix the nucleus to the pipe cleaner.  This can be done by pushing the pipe cleaner through the center of the nucleus.  Reinforce the nucleus with more glue dots.

8.  We previously determined the distribution of electrons for the carbon atom.  Carbon has six electrons.  The first shell has a capacity of two electrons.  Add two of the crafting beads to a pipe cleaner.

9.  Now wrap your pipe cleaner around the nucleus of the atom to form the first shell.  Secure it.

10.  Repeat step 9, but for the second shell.  The second shell's carrying capacity is eight. Carbon's four remaining electrons will have plenty of room:)

Enjoy your atom!!!

Resources to use in the classroom:

• This website allows your students to use an interactive simulation to build an atom.
• This website  allows your students to explore the atomic structure of any atom by simply choosing an atom from a drop down menu.

Resource for the teacher:

The Disappearing Spoon is a great read for teachers that will be exploring the Periodic Table of Elements in their classroom.  This book is full of interesting stories about the history and magnificence of the elements and their discoverers.   Take these interesting stories to your classroom and engage your students!!!

Lava Lamp Demonstration

What you will need:

• a clean bottle of any kind
• baby oil or vegetable oil
• 3/4 cup of water
• food coloring
• fizzing tablets (Alka-Seltzer)

Instructions:

1.  Pour the water into the bottle.

2.  Pour the vegetable oil into the bottle until it is almost full.

3.  Observe the water and oil separate forming layers.

4.  Add 15 drops of food coloring to the bottle.

5.  Observe the food color mix with the water.

6.  Break the fizzy tablet into pieces and add a little at a time, or add the entire tablet at once. The tablet will sink to the bottom and the show will begin!!

7.  When the reaction stops working, just add another fizzy tablet!!!

How it works:

The first thing that you should have observed in the beginning of this demonstration is that water and oil do not mix!! This is because the water molecules are not attracted to the oil molecules.  You could even say they are mortal enemies.  To demonstrate this, shake up the bottle once you have the oil and water in the bottle.  The oil breaks up into tiny bubbles, but never mixes with the water.  When you add the food coloring, you will notice that it mixes with the water, but never mixes with the oil.  We could infer that the food coloring is the water's ally in the battle of molecules scenario. 

The second observation to detect is the liquids in this experiment form layers.  This is a great illustration of density.  Density is the characteristic property of a substance that shows the relationship between the mass of a substance and how much space it takes up (volume).  We can quantify density using the equation D = M/V.  The oil floats on top of the water because it is less dense.  The food coloring has the same density as the water, so it sinks through the oil and mixes with the water.

And finally, when you drop the fizzy tablet into the bottle it sinks to the bottom and starts to dissolve.  As the fizzy tablet dissolves, it reacts with the water to form the gas carbon dioxide (CO2).  The carbon dioxide gas is less dense than the water, so it floats to the top.  When the gas bubbles pop, the water sinks to the bottom again. It does this over and over until the fizzy tablet is completely dissolved!

Demonstration Extensions:

• Does the temperature of the water affect the reaction?
• What happens when you put the cap on during the reaction?
• Does the size of the fizzy tab affect the amount of bubbles produced?