This talk covered a lot of ground regarding hydrates, anhydrates, and the chemistry way of counting by moles. Many compounds are formed by reactions that occur in water and appear to be dry, but when heated release water. This concept seemed like a pretty simple one. The substance left over after heating is called an anhydrate. I learned that moles are the best way to count things having to do with the number of atoms. Just like a dozen is twelve, moles just happen to be 6.022 x 10^23. When it comes to calculating things though with moles, things get a little tricky.
- Explain the electron sea model: Metals are held together by metallic bonds. These bonds are formed when atoms in the metal share valence electrons with each other. Large spheres in the sea represent cations. The small circles represent electrons. The electrons are always in a constant motion around the cations, never belonging to anyone one cation. There are all a part of one metal crystal. The electrons are moving in a sea like fashion, effectively holding the cations in place.
- What is meant by malleability? Malleability has to do with how easily electrons are able to move about in a metal crystal. The more the electrons are able to move, the more malleable or bendable the metal is. And vise versa.
- Describe the properties of three different types of metal: Spring steel is steel that springs back into place after bending it. Annealed steel is steel that is easily bendable. Tempered steel, what most tools are made from, is a firm steel that is hard to bend and stays in place.
This Chem Talk started out with a review going over the electron-sea model for metals. This is a picture of a sea of electrons surrounding cations. Metals are held together by sharing electrons. Metals though sometimes do not hold on tightly to their valence electrons. Because a metal’s electrons are so free to move around, the atoms in most metals can move past each other. This is called malleability. This has to do with how easy or hard it is to bend a metal. Alloys are when other elements are mixed with metals to form another substance. Alloys are most often stronger and more reliable to use. The human species started using alloys as long ago as 100,000 years for tools and weapons. The talk also goes into detail about how steel can be molded and changed. When a steel atoms, are hot, they can be shape shifted because their atoms are unlocked. But when the steel is cooled down, the atoms are locked into place again. This is how blacksmithing works.
- Na – 1 F – 7 Mg – 2 Ne – 8 P – 5 Al – 3
- a. Na – (-1) F – (+1) Mg – (-2) Ne – (0) P – (+3) Al – (-3) b. Na – (-) F – (+) Mg – (-) Ne – (+/-) P – (+) Al – (-) 4. To perform the opposite process, you would just change the terminals to which the copper and nickel are connected to. 5. Mg – Mg^2+ 6. Cl – Cl^1-
This Chem Talked acted as a review for me. It went into more depth about valence electrons and where they are located, as well as the octet rule. Nothing really new was learned. Although, it was interesting to learn about which metals are most and least active when it comes to oxidation. The most active metals like iron can loose electrons easily and form compounds regularly. Other metals though are able to form a layer on top of themselves, like for example when aluminum forms aluminum oxide, which acts as a protective layer from chemicals in the air. This is why so many buildings and structures are made with copper. Copper forms a natural protective coating that shields itself from the elements. In the future, I will be sure to put a copper coating on the top of my house so that it will be protected even from the harshest of corrosion.