Today's Quote:
Brain Bender:
In what year did Christmas and New Year's fall in the same year?
Recap:
In 8th grade we dove in depth into the atom and how electrons(-) place themselves within the electron cloud. To do this we had to be very familiar with the periodic table and how to use it. I pointed out that the rows on the periodic table are called Periods and there are 7 total. They represent the shell or orbit in the element in question. For example Hydrogen (H) is in the first period so it has one electron orbit while Tantalum (Ta) is in the 6th period and will have 6 electron orbitals. In order to calculate the MAXIMUM number of electrons at any given energy level, I provided the basic formula 2n2 where the variable "n" represents the energy level (1-7) in question. If I wanted to calculate the MAXIMUM number of electrons at energy level 5, I would plug 5 into my formula 2(5)2= 50 possible electrons This method helps us draw a Bohr diagram of atoms. I asked the classes to think of the Bohr diagram as a neighborhood. Each energy level/orbital represent a street and the number derived from the formula represents the MAXIMUM number of open houses on that street. I also pointed out that atoms like to fill their inner energy levels before moving to the next higher one.
When it comes to determining the number of electrons in each energy level you simply look at the atomic number and begin filling the empty slots on the level. For example, Carbon has an atomic number of 6 which means it has 6 protons and 6 electrons. Carbon sits on the 2nd period and has two energy levels. Since the first energy level has a maximum of 2 electrons the remaining 4 would be on the 2nd energy level and Carbon still has 4 available "houses"to use for bonding with something else.
We're not really concerned with the electrons at the inner levels but only the one located in the valence. This will tell us how atoms bond to other atoms to form molecules. In order to see this it's helpful to draw Lewis dot structures. I provided a short video that gave a very simple way to draw Lewis structures. Basically you put the element symbol in the center of the page and list it's protons and neutrons in the nucleus. Then, draw cross hairs on it. REMEMBER, we are only looking at the electrons in the outer shell. This number is easy to determine by looking at what family/ group the element falls into on the periodic table. For example, Boron (B) sits in Family #3 which means it will have 3 electrons in it's outer shell. The Lewis structure would look like this:
We touched on several properties of elements but will go more in depth this week.
In 7th grades we had students share their stories which were very creative and incredible and then add them to the Wall of Awesome in the hall. Students then began to watch the video Secret Universe The cell. I kept pausing the video to interject explanations and answer questions. Students should be completing the question worksheet as they watch. We will finish the video today after candling our eggs.
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Agenda:
8th grade Honors:
Complete building of the cloud chambers. If there is time, properties of matter.
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7th grade Honors:
Candle eggs and add drawing and data to your data sheet. Finish video on cell.
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8th grade physical science
Read Chapter 9 section 2 and complete the Section Outline. Due at the end of class.
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