Week 8&9 Reflection

        To continue our exploration of Unit 6, our SG Chem 2 class spent over a week learning about the concept of naming compounds. We began at the beginning of last week through a packet that introduced us to ionic compounds. To start the packet, we were given the number of atoms of two elements, and we had to write the formula of the compound and draw a particle diagram. At first I was confused about why we were doing that packet; it was nothing different from what we had done before, and it seemed too easy. I felt like I was missing the point, and I soon found out that I was. A few questions later in the packet, it asked to look back at the patterns of the compounds we had formed. After examining the formulas for a while, I noticed that each compound was composed of one metal element and one nonmetal element. When we discussed the question in our small groups, I also came to realize that the elements had certain charges, and that the charge of each compound as a whole was always equal to zero. After the realization of this concept, the packet began to make a lot of sense to me, and I was able to predict the formulas of certain compounds and answer the remaining questions with ease. When the whole class was finished with the packet, we recollected as a class to go over what we had learned. As a group, we were able to conclude that ionic compounds are compounds composed of one metal element and one nonmetal element, and the charges of the elements are always balanced. Later on, we were introduced to the criss-cross method, which is a technique designed to help determine the chemical formula of an ionic compound if the charges of the elements are known. I found this method to be very helpful when naming ionic compounds, and a good way to make the work as simple as possible and eliminate errors. Below is an example of the criss-cross method and how it is used:

        After learning about naming ionic compounds, we continued on to a different type of compound; molecular compounds. With the help of another packet, the class was walked through the process of naming molecular compounds, and learned how the process differed from naming ionic compounds. At first, I couldn't see the difference between ionic and molecular compounds, and I was confused about why molecular compounds had a special way to be named. After going through a few of the questions in the packet, it came to my attention that all the molecular compounds I had seen were a combination of a nonmetal element and another nonmetal element. When I realized this, it made sense to me for a few minutes, but then I was confused again. I wondered how nonmetals could combine with other nonmetals because the charge of a nonmetal is negative, so the charge of the compound as a whole would not equal zero. Then I remembered that ionic and molecular compounds were two different things, so I came to the conclusion that this must be one of their differing factors. After establishing this separation between ionic and molecular compounds in my head, the packet went on to talk about the prefixes used in naming molecular compounds. The concept of prefixes made sense to me, because they basically showed what the chemical formula of a molecular compound was. I also soon came to realize that prefixes are used because of the fact that the charges in a molecular compound don't equal zero, so a form of clarity is necessary when naming the compound. In an ionic formula, prefixes are not needed due to the ability of adding the charges to determine the formula of a compound. The realization of these concepts brought me a greater understanding of both ionic and molecular compounds as a whole, and helped guide my way throughout the remainder of the unit. Attached are some examples of naming molecular compounds:

        Towards the end of this past week, our class took the Unit 6 Test. I thought it was definitely the most challenging test we've had so far; I felt well prepared going into it, but during the test I thought differently. The multiple choice section was fairly tricky; there were some questions I was stuck between two answers and not sure which one to put down. The naming section was difficult as well, and I feel like I probably made a few errors here and there throughout. In some questions, part of the compound contained a polyatomic ion, but at times I wasn't sure if I was supposed to name it with the name of the ion or in just a basic way. After the naming section, I was stuck on the problems with the tape for a while because I was confused on the way they were set up. It was only after a while that I realized the tape was on the right hand side, not the paper and the metal, and that helped to clarify the diagrams. Now that I think about these problems, I think I forgot to mention that the electrons move in the metal because it is a conductor of electricity, whereas the electrons in the paper are attracted to the tape, but not a conductor of electricity, so they only shift to the side of the atom. During the test, I remembered that we had talked about problems just like those, but at the time I had a hard time remembering what exactly we had said. The last part I had trouble on in the test was towards the end with drawing a representation of a compound, and then showing how it splits into individual ions. I had no problem splitting the compound into its separate ions, but I did have trouble drawing the compound in the beginning. I was confused on how exactly the compound should be represented; since it contained a polyatomic ion, I wasn't sure if I would supposed to draw each element that made up the ion individually, or one atom that contained the ion as a whole. Overall, I definitely think the test was challenging, but I gave it my best effort, and the mistakes that I made will only be ones that I will be able to grow and improve from.