Variety of Atoms
We reviewed what we have learned about atoms; that they are the building blocks of creation, and we likened them to Legos. We sorted a batch of Legos into to piles according to size and color. We then designated the white 1 x 2 Legos as hydrogen, the red 2 x 4 Legos as oxygen, black 2 x 4 Legos as carbon, green 2 x 4 as chloride, yellow 2x4 as sodium and grey 2x4 as calcium.
With these atoms, we could build several molecules: NaCl (salt), CaCo3 (chalk), H2O (water) and CO2 (Carbon dioxide).
Then we looked closer at the atom itself. We made this huge diagram of an atom. I mean HUGE. It takes up most of the wall in our dining room. We reviewed that the nucleus contains the protons and the neutrons, and that these make up the mass number. We glued on pictures from Real Science 4 Kids Chemistry Level II of the electron orbitals.
We reviewed that the atom is held together by negatively (electrons) and positively charged particles (protons). The atom also has a third particle (neutrons) which are neutral in charge. The number of protons an atom has is its atomic number.
Clouds, Shells and Orbitals
In the Friendly Chemistry text, there is a diagram of a section of the atom, that they have transformed into what they call a "Doo-Wop Board" (don't ask me why, because I don't know why they call it that.) This tied in nicely with our huge atom diagram.
So we get out our "Doo-Wop Board", thick piece of paper that you put in a baking tray and then the magnets can stick to the board. I explained how the electrons go on the board...each magnet represents one electron, the yellow one going in one direction (let's say clockwise) and the gray ones going in the opposite direction (let's say counter-clockwise). They learn that for the S or spherical orbitals, one gray and one yellow electron goes down, and for the P or pear shaped orbitals, they go down one on the x position, one on the y position and one on the z position and then the second is put in the x, y and z positions. They have the huge atom right on the wall to refer to when thinking about the different orbitals.
When we got to talking about how important the valence electrons are, we were inspired to make our own model of a molecule using floral wire and beads. We had wanted to make a 3-D model using jewelry wire, but none could be found and we didn't want to wait, so we made this flat model. We talked about how the oxygen atom has six valence electrons and that the outer shell of molecules strive to fill all of their possible eight valence electrons. Then we talked about how the hydrogen atom only has one valence electron, but if two hydrogen molecules and one oxygen molecule could come together, then all three molecules could become happy!
The Periodic Table of Elements
We looked at The Periodic Table of Elements and at how the elements are arranged. We also looked at the numbers and letters in the different blocks and what they meant. We looked various element's atomic numbers on the periodic table, and then made the atom on the "doo-wop board" until they could do them on their own.
We talked about how some of the atoms are very stable while others are not, and that we could tell an atom's stability by knowing its number of valence electrons. We also talked about how the stable atoms are called nonreactive, inert or noble atoms. All of these atoms have all eight electrons in their outer shell. This is covalent bonding.
|Physical vs Chemical Change|
We have looked at how atoms work together to make a chemical reaction. Hydrogen Peroxide has two hydrogen atoms and two oxygen molecules, which makes it only one oxygen molecule different than water. It is unstable because it needs to get rid of the extra oxygen molecule and so it always trying to combine with whatever it can to release the extra oxygen molecule. Normally this happens very slowly, but when you add yeast to it, the reaction is sped up and the hydrogen peroxide quickly combines with the other chemicals to release its extra oxygen molecule. This is called a catalyst.
Another kind of bonding occurs when negatively charged atoms are attracted to positively charged atoms. We talked about this in terms of the bond that table salt has. Sodium has only one electron and therefore is unstable, but it decides that it is easier to lose his lone electron rather than try to gain seven more. Chlorine, on the other hand, only needs one more electron. These two substances, then, are extremely attracted to one another. This giving-taking bond is called an ionic bond.
sources and resources:
sources and resources:
- Exploring Creation with Chemistry and Physics, Jeannie Fulbright
- Friendly Chemistry
- Real Science 4 Kids Chemistry Level II
- How to Smile: Lego Chemical Reactions