Elements, Atoms, and Molecules Two Days

Transcription

1 Elements, Atoms, and Molecules Two Days Genevieve Wilde Mentor: Mrs. Kippy Russo Roosevelt Junior High School, Altoona Room March Grade Level and Topic This lesson will be taught to seventh grade students. In this lesson I will attempt to guide the students to an understanding of the connections and differences among elements, atoms, and molecules. Keeping the next day s lesson in mind (compounds and mixtures), I will lead the students naturally to the following day, in order to make a smooth transition to the next topic. Applicable Pennsylvania Science Education Standard(s) 4.7.A. Describe concepts about the structure and properties of matter. Identify elements as basic building blocks of matter that cannot be broken down. Instructional Objectives With the use of many examples, models, worksheets, and activities, students will be able to distinguish between atoms and molecules. Students will remember the acronym for diatomic elements (HONClBrIF pronounced honckle-briff) Students will keep a science notebook (a bluebook) with which they will take and keep all notes from class, and refer to the notes if necessary. In addition, Students will complete the 4-page worksheet on molecules and atoms and hand them in after class (or, for the shorter afternoon classes due to PSSAs the worksheets may be done for homework). Teacher will provide enough guidance in students notebooks that the students will be able to refer to and understand material in the upcoming days lectures. Keeping in mind the complexity and difficulty of chemistry, teacher will keep the lesson very simple, using as few vocabulary words as possible, in order to maximize understanding of actual concepts and minimize intimidation. 4. Materials, Equipment, & Set-up Blue books (1 per student, with a few extras in case they make mistakes) 2 molecular model kits with pre-made models of N 2, O 2, C 6 H 12 O 6, NaCl, Caffeine, Aspartame, and Vanillin ATOMS or MOLECULES worksheets Correcting markers or colored pens

2 5. Body of the Lesson (70 minutes) In order to construct the molecular models for substances listed in materials and methods, the following diagrams should be used. Molecules should be made AHEAD OF TIME to save time. If time is left over at the end of class, molecules may be taken apart and students given an opportunity to see/construct some of the other molecules listed on the Other Molecules appendix page. Caffeine Introduction of Molecules Aspartame I. Since molecules, elements and atoms are frequently confused by students, this lesson will take a sufficient and deliberate amount of time to ensure a clear understanding. After discussion with my mentor, we thought it would be best to lecture a maximum of 15 minutes at a time, since the Rule of Thumb is The students will pay attention 1 minute of class time per 1 year of age (13 years old, plus 2 minutes just to be efficient).

3 II. (15 Minutes) Atoms and Elements EXPLANATION: In the past two weeks students have been researching and studying the different elements on the periodic table to finish their benchmark projects and presentations. Everyone please open their books to the periodic table (p ). Elements are the building-blocks of matter. Everything is made up of elements, and we learned that an atom is the smallest particle into which an element can be divided and still be the same substance. When atoms of different elements are combined in different ways, they take on different properties. These groups of combined bonded elements are called molecules. EXAMPLE: So, for instance, I can draw one atom of Potassium (K) Who had Potassium as their benchmark? What can you tell us about potassium? Metal or nonmetal? What color? Consistency? React with anything? Potassium is a soft, silvery-white metal, which reacts violently with water. KOH, or potassium hydroxide, is white crystals, and is a very strong chemical used in making soaps and bleaching things. KBr, or potassium bromide, is also white crystals, but acts kind of like table salt in water. It is an effective medication for seizures, and is commonly used to aid in the treatment of epilepsy. KI, or potassium iodide, is taken as tablets after exposure to severe radiation (like nuclear bombs). When bonded with many more different atoms of different elements, potassium can takes part in many more molecules, like C3H3O3K1, or Pyruvate, which is an energy molecule in plants. Some elements only occur in pairs, naturally. These are H, O, N, Cl, Br, I, F altogether, honcle-briff! III. (27 minutes) PRACTICE: After the discussion of elements, atoms, and molecules, I will take two minutes to explain the notation used to write molecules (with the symbol and subscripts). This will allow the students to feel a little bit more comfortable completing the worksheets. Afterwards, students will write their names on their papers, work on the worksheets individually for 10 minutes, and then get into pairs or triplets and discuss their answers for 5 minutes. Finally, for 10 minutes the whole class will go over the answers to the worksheets. Students may not change their answers, but mark down the correct answers in marker or pen. This is for assessment purposes. Draw to students attention the different molecules. Where have they heard of Penicillin before? Advil? Chlorophyll? DDT? (*think eagles eggs!) Cholesterol?

4 IV. (15 minutes) Collect papers. Do not go over extra-credit question until papers are collected. ELABORATION, ASSESSMENT: A. Hold up water molecule model Can anyone say what molecule this is? Mention: Where are the electrons? Mention: Where are the nuclei? Protons, neutrons? B. Explain that different colours stand for different elements, when using the models. Also explain that the sticks signify that the atoms (represented by spheres) are bonded together. C. To be written in Chemistry Notebooks: Do not discuss! How many molecules do you see? (1) How many atoms do you see? (3) How many elements are represented by this model? (2) D. repeat with caffeine. (1) (14) (4) Teacher may tell the students that there are fourteen spheres (not balls could get silly), so that they don t have to count how many there are from their seats. E. Have students put their pencils down, then go over answers to questions and explain. They may write the correct answers in marker, so that they have the right answers in their books. Students may not change their answers! This is so that their understanding of the material can be assessed later by the teacher. Incorrect answers in the Chemistry notebooks or worksheets may signify important points to review next day. V. (Rest of class period) WRAP-UP: Students may work on their element packets for the rest of the period, or sit and talk/color/draw quietly. Teacher will pass molecule models around for students to look at. possibly build other molecules from the Other Molecules list in Appendix. Teacher may practice memorization of names by asking students for suggestions of chemicals or molecules they would like to see represented next class. 6. Instructional Asides Students in Mrs. Russo s 2nd period expressed interest in having chocolate actually in the lesson, since they heard my lesson might be related to chocolate. I will therefore bring some mini bars of chocolate (and some other candy in case there are allergies) for all periods as prizes. Since I have noticed that a few of the students (specifically two in first period, and a few in third period) have a difficult time writing and keeping on task, I will make the notes in the Chemistry notebook very simple, and to the point, and give them time to copy things down. I have made the worksheet lines and fonts large, to give the students more room to write.

5 7. Valuable Resources to Remember:

6 APPENDIX A: Other Molecules of Interest Chocolate Vitamin C Vinegar Codeine Lactose

7 APPENDIX B: Worksheet ATOMS OR MOLECULES???? In the spaces below, indicate whether the substance exists naturally as atoms or molecules. BE CAREFUL to say whether it exists as atoms or molecules in its usual or natural state (in our part of the atmosphere)!! The first one is done for you. Gold Atoms Potassium Bromine Sugar Water Chalk (calcium carbonate) Carbon Cesium Coffee Nitrogen Titanium Table Salt CHALLENGE: Think hard! Which elements make up the following compounds? Look at your periodic table (on page 106 in your book) for correct spelling of elements. You will lose points for spelling errors! Sodium Chloride: Sodium, Chlorine Hydrogen Iodide:, Calcium Carbonate:, Nitrous Oxide:, Potassium Bromide:,

8 Tricky! -- Cinnamon (C H NO ):,,, How Many Atoms of Each Element? For each molecule below, write the names of the different elements found in the molecule, and how many atoms of each element are in one molecule of the substance. MOLECULE ELEMENTS # of atoms in one molecule? Penicillin (C16H18N2O5S1) 1. Carbon Advil (C13H18O2) 1. Chlorophyll (C37H42Mg1N4O7) 1. 4.

9 5. MOLECULE ELEMENTS # of atoms in one molecule? DDT (C14H9Cl5) 1. Cholesterol (C27H46O1) 1. CHALLENGE: Garnet (Al Ca Fe Mg Mn O Si 1. Interesting facts about garnets: January s birthstone! Commonly given to signify an 18 th wedding anniversary )

10 7. EXTRA CREDIT: Name the very important biological molecule pictured below. (HINT #1: It s name is represented by three letters, and genetics scientists know all about it!) (HINT #2: It s full name is deoxyribonucleic acid )

11 REFLECTIONS: This lesson seemed like it was going smoothly at the time. However, after having read and graded the worksheets and notebooks, I can see that I might not have been as clear as I would have liked. Only one person got all five of my brain-scratcher questions correct. The quiz at the end of the lesson served as a good indication of how many students actually got the material, and understood it enough. I was able to assess how much they knew, and then, next day, review and touch upon a few things that I missed in the previous lesson (which turned out to be extremely important definitions!). After going over the worksheets and reviewing again, the students finally seem to understand what is going on. I will have to assess again, probably during the Jeopardy Game on Friday, March 24. The huge bag of chocolate candy worked well to get the students to answer questions. I find that it cut wait-time enormously. However, I m wary that this might not give students enough time to think if they need it. Since then I have begun to say things like, How about someone I haven t heard from already to give everyone a chance to answer questions and earn candy. The 70-minute period was an incredibly long time for the students to sit in their seats and take notes. 1 st period is an especially rough time for the students to stay awake (because of the early hour). In future lessons I will have to incorporate ways for students to remain active (and avoid mental/physical clotting). Though notes are important, they are not worth sacrificing the class s wellbeing to complete. After this lesson, students seemed at least partially ready for the lesson on compounds and molecules, and, after a short review, they should be able to distinguish between molecules, elements, and atoms. After these few lessons, I feel confident with at least 90% of the names of the 1 st period class. I have noticed a difference in responsiveness among the students, and the memorization is making class much easier, since I can call on someone without saying Yes, you. 2 nd period is roughly 50% memorized. The common names (Kaylie, Kylie, Cylie, Kaitlyn, Kelsey) are more difficult than I expected. 2 nd period had presentations during the beginning of the class period, and I was only able to get half of the notes finished in the short amount of time we had. Planning has made this easier, since they will have an extra day to catch up while the other periods are watching a movie. I moved more quickly with period 2, as expected I will just have to be careful to keep assessing how much they know with challenge questions (in their lab notebooks) to make sure I haven t glossed over anything. They should be ready for the ph 39 Drops Lab by Monday.