The+Periodic+Table



I know that you said that you feel comfortable with the periodic table, but I need to go over it a few times since it is a really important part of 8th grade. Just answer a few questions and tell me if you needed a book or you knew it off the top of your head.

1) The vertical columns are called? the horizontal rows are called? and why are the elements in these columns and rows grouped together?

The vertical columns are called families (top of my head) and the horizontal rows are called groups (top of my head). The elements in the periods and groups are together because they have similar properties (book).

2) What do the numbers at the top of the elemental entries mean on the periodic table you chose?

The numbers at the top of the elemental entries are the atomic numbers which mean how many protons and electrons are in the element.

3) What can't you tell me about the elements with the PT you chose?

The number of neutrons the elements have.

Group 1's atoms all are highly reactive, have one valence electron (one electron on their outer ring), are silvery, are solid, have a low density, and low melting points. When you combine group 1 (alkali metals) with halogens (group 17) you get salts.


 * Your answer is a good sign Jason! We'll move on from this point. Can you describe what an Isotope and an Ion are and give me some examples? Use Sodium as your example.**

Isotopes are atoms that have the same number of protons in the nucleus, but different numbers of neutrons. (Every atom has an isotopic form)

Ions are atoms that have given up or gained an electron, becoming positively or negatively charged.

Normal Sodium Atom:

Sodium Isotope:

Sodium Ion:

Mystery Lab:





We use the orbital model in school because it is much easier to draw and because it is much easier to understand than the quantom mechanical model.

The quantum mechanical model is more scientifically accurate than the orbital model; that is why scientists use it.

Absorption and Emission Spectra of Hydrogen



I think a Hydrogen ion would have a slightly more blue spectra if it was positively charged and a slightly more red spectra if it was negatively charged. The same would be with isotopes, the higher number of neutrons the more blue, and the lower number of neutrons the more red. I came to this conclusion because the extra electron might block out more red, or the loss of an electron would let the larger, longer wavelengths of red through. Red shifted Hydrogen atoms would have a slightly more red spectra than normal and blue shifted Hydrogen atoms would have a slightly more blue spectra than normal.
 * How could the spectra of an element change? ...**

In any case, If we get a light spectra from an object that is moving away from us at speeds near the speed of light, the light gets stretched out and you get a longer wavelength. A longer wavelength correlates to a shift towards the red end of the spectrum. If an object is flying towards us near the speed of light the waves get smooshed up and therefore have a shorter wavelength. The spectrum appears to shift towards the blue end and is why we call it "blue shift". The type of light given off a particular element corresponds to the distance between the orbitals and the atomic radii as well as the electrons. So an isotope of H might look similar to the spectrum for regular H, but there would be a shift in the spectrum one way or the other. In Ions you may find that because the element has more or less electrons it is more or less receptive to other electrons. Therefore you may have a brighter or dimmer spectrum.


 * The Trouble with Space Vans project:** __**What are real spacecraft made of ? Tell me why the engineers probably used the materials they did. Think about the materials and their properties on the periodic table. You don't have to get super deep into this, let's just aim for general ideas. Dad might be able to help out here. Now think about making a space van for your personal use in space. Would you stick with what the builders of real space craft use, or would you use something different? Regardless, describe chemically why you would do what you would do. Think about the properties of metals, non-metals, and metalloids.**__

Real Space Shuttle's main components:

Its TPS ( Thermal Protection System ) is made up of ceramic tiles and other materials.

The TPS covers a mostly aluminum "hull". The TPS is essentail because areothermal heating, heating caused by the frictions of air and the shuttle, is well over the melting temperature of aluminum ( 1220 Degrees Fahrenheit or 660 Degrees Celcius ).
 * What are ceramic tiles made of? Why do you think this material insulates from heat so well?**

Ceramic tiles are made of clay that is molded, and then fired. This works well because clay is made up of elements like iron, calcium and sodium, which all have fairly high melting points.

The tires of space shuttles are reinforced normal rubber tires, but instead of inflating them with oxygen, which corrodes and is explosive, they inflate the tires with nitrogen.

The space shuttle has SRB ( Solid Rocket Boosters ) for takeoff, and has an external fuel tank that stays attached until the shuttle is orbiting. The orbiter ( Main Part) of the shuttle has three seperate engines attached to its end, which it uses while in space.

My Space Van: aluminum/titanium alloy hull ( aluminum because of its high melting point and light weight, and titanium because of is strong resistance to acids )
 * Explain why you want the Space Van to be acid resistant.**

I would want my space van to be accurate because on alot of the other planets, the atmosphere contains some form of acid.

I would have a TPS similar to the space shuttle, but I would only use materials that were highly reuseable because I might need to enter other planets' atmospheres many times.

My space van would probably have the same characteristics as the space shuttles' tires, but would I would have a lot of smaller tires that are cheaper.

My space van would have SRB also, and would have an external fuel tank. But unlike the space shuttle, my van would have a large internal fuel tank which would be used not only for flying in space but also for taking of from other planets.


 * //You are doing a great job of explaining physical and chemical change. When you are done there let's strat talking about acids and bases. If you wanted to start a new page for that you could get some simple definitions posted.//**