Unit 3: Atoms and Elements: Classification Lab name:_______________________ period: _________________ Part 1 What does it mean to classify a group of objects? Background: ______________________________________ is the process of grouping things based on their similarities. Chemists use classification to organize __________________________ into groups so that they are easier to study. Elements are made up of ______________. We use the ____________________________ to organize the elements based on their atomic properties; the elements are ____________________________ which means their properties have a regular repeating pattern. By using these patterns, we can predict the properties of unknown elements. Periodic Elements Periodic Table Procedure: 1. Gather a set of manipulatives from the center lab table. 2. In your group, plan out how you could organize them. (this could be the size, color, shape, mass, or something else!) 3. Place your group’s objects on the lab table in the same way you would organize them according to your plan. 4. On the next page, draw your group’s system of classification. Make sure to include a key that explains how it is organized! Extend Yourself With your lab group, come up with more than one way to classify your set of objects. In a TAGS response, answer the following question: “Is one of the classifications more ‘correct’ than the others? Why?” Classification Young Mendeleev says: “An organized student is a successful student!” Atoms Unit 3: Atoms and Elements: Classification Lab Look at your objects carefully and list 6 different methods that you could classify them. Choose one method and separate your groups. Describe why you chose this method. Extension: Describe how/if you can use more than one classification at the same time. Draw your organized chart here. USE A RULER!! Unit 3: Atoms and Elements: Classification Lab Directions: Open up your lab table notebook to find directions for your tests. In your group, you will complete two or three tests on the samples at your table. In the boxes below, record your observations and inferences. Test 1 What will you be testing? What observations do you expect to make? What do you expect these observations to tell you? Do you think you will find any patterns? Observations (at least three): Inferences In the space below, describe what patterns or properties that you infer from your observations. Support your inferences by linking them to your observations with an arrow. - 1. 2. - 3. - 4. - 5. - Unit 3: Atoms and Elements: Classification Lab Directions: Open up your lab table notebook to find directions for your tests. In your group, you will complete two or three tests on the samples at your table. In the boxes below, record your observations and inferences. Test 2 What will you be testing? What observations do you expect to make? What do you expect these observations to tell you? Do you think you will find any patterns? Observations (at least three): Inferences In the space below, describe what patterns or properties that you infer from your observations. Support your inferences by linking them to your observations with an arrow. - 1. 2. - 3. - 4. - 5. - Unit 3: Atoms and Elements: Classification Lab Did you know? Professional scientists often share data with each other when they are researching similar things. Directions: In the space below, record the data that other groups report during our discussion. You will use this information later when you try to classify atoms based on their chemical and physical properties. Group Number __________ What was tested? Group Number ____________ What was tested? What patterns were inferred? What patterns were inferred? Group Number ___________ What was tested? What patterns were inferred? Group Number __________ What was tested? What patterns were inferred? Unit 3: Atoms and Elements: Classification Lab Summarize: In the space below, summarize the patterns for chemical and physical properties our class observed. This can be done in a table, in bullets or in paragraph form. Chemical Properties: Physical Properties: Name: _____________________ Period: ________ Unit 3: Atoms and Elements: Classification Lab 1 8 The Mystery Element Identification Game! Which element is which? Use your periodic table, lab data and patterns of chemical and physical properties of atomic families to fill in this blank periodic table. Include the letter of the unknown element, the element’s name and how you identified the element from the clues given. 1 Be careful… they won’t all be present or in order. 2 2 3 3 4 5 6 7 Unit 3: Atoms and Elements: Classification Lab Chemicals in the stockroom: CaCl LiCl SrCl KCl HOOH K2CrO4, K2Cr2O7 KMnO4 Al2(SO4)3 NaAcetate Bleach CuCl2 Na2SiO3 NaHCO3 Vinegar Si Na Mg Sucrose Borax Phosphorus (from matches) Al (foil) Objectives SW classify a group of objects (chemicals) by their physical and chemical properties Activity - intro classification - atomic properties classification practice Tests: pH of solids and solutions Conductivity of solids and solutions Solubility Reading/video on noble gasses? Reading/video on halogens? Video/demo of alkali metals and water Density Shine and ductility flammability Assessment Classify and order unknown samples / prompts Differentiate/Remediate Unit 3: Atoms and Elements: Classification Lab Reactivity with water (1) Li, Si, Al We know that we’ve observed a reaction when bubbles, heat, sparks or chemical properties change when two substances come together. One group on the periodic table reacts explosively with water when under the right conditions. Example: Heat and bubbles are formed when some groups on the periodic table come into contact with water. You will be given samples of Aluminum, Silicon, and Lithium and sugar. One at a time, place a small piece of the samples into water and record what happens. Unit 3: Atoms and Elements: Classification Lab Testing for acidity Using pH strips (1) NaOH, HCl, vinegar, H2CO3, borax solution Acids and bases can discolor clothing, burn skin and lungs, and corrode metals. You must use EXTREME caution when working with these chemicals!!!!!!! There are substances which have the property of changing their color when they come in contact with an acidic or basic environment. These substances are called pH indicators. We can use special papers which have been soaked with indicators to tell the pH of a solution. These papers change color when they are immersed in acidic or basic liquids. This is the case of the well-known litmus paper. Using Litmus paper. To use litmus paper, simply touch the paper to the sample you want to test. Try it with your solid sample first, then test the liquids. Remove it immediately and compare the color of the paper to the provided scale. A pH reading from 0-7 means that your sample is acidic. A pH reading of 7-14 means that your sample is basic. Procedure: 1. Touch the test strip to each of your solid samples. Observe any color change you notice on the test strip and compare the color to the key on the package. 2. Record your observations. 3. Pour water in each of your solid samples. 4. Dip a pH strip in a liquid sample. Observe any color change you notice on the test strip and compare the color to the key on the package. 5. Repeat step 4 with a new pH strip for all of your samples. 6. Record your observations. Unit 3: Atoms and Elements: Classification Lab Testing for solubility (2) NaCl, CaCl2, Si, Al, AlCl3, sugar In a solubility test, we are observing how well our substance mixes into the solvent (the liquid). We consider a substance soluble if the solid crystals disappear when they are mixed in. NOT Soluble Procedure: 1) 2) 3) 4) 5) 6) Soluble Perform the solubility test only AFTER you have tested the conductivity of your DRY samples! Note the amount of solid in each of your beakers. Have a team member get a sample of water from the sink Pour water into each beaker until the beaker is half full, and then stir it. Compare the amount of solid at the bottom of your beaker to your starting amount. Record your observations. Unit 3: Atoms and Elements: Classification Lab Testing for conductivity using a digital probe (2) NaCl, CaCl2, sugar, AlCl3 Electrical Conductivity refers to a substance’s ability to transfer electrons. Our digital probes can tell us a solution’s conductivity on a scale of 1-10. A low reading (1-4) means that electrons cannot flow between particles easily. A high reading (7-10) means that electrons can move with ease. Procedure: 1) For this test, we will look at the conductivity of crystal samples before studying the conductivity of solutions. 2) To use our probes, press the button on the side of the probe and you should see a red light next to the ON text. You must hold the button down for the probe to take measurements. 3) Dip the metal ends into the chemical you want to test and watch the scale on the front of the meter. If the meter doesn’t light up, it means that the sample is NOT conductive. 4) Record the conductivity of each sample in your observations. 5) Once you’ve measured the conductivity of each dry sample, complete the solubility test. 6) Once you’ve completed the solubility test, repeat steps 2-5 for your solutions. Unit 3: Atoms and Elements: Classification Lab Reactivity with Oxygen (3) H2, cellulose, N2, Mg Density Mg, Al, Si Noble Gases (3) http://noblegases2.webs.com/argon.htm Maleability Mg, Al, C (graphite) Physical appearance (3) Mg, Al, S, C, B, air? Unit 3: Atoms and Elements: Classification Lab Argon, Hi people, as you know I’m Argon, or the Jealous one, that’s what the rest of the no good, creditstealing family calls me. I mean seriously I’m in NEON lights and HELIUM balloons but you don’t hear it being named after me. As you can probably tell I get angry real easy and I hold grudges for a long time, (Argon has a boiling point of, 185.85°C or -302.53°F). I also get upset really easily (Argon has a low melting point of, -189.35°C or -308.83°F). I have a lot of the same characteristics as the rest of my family, for example I am (odorless and colorless). I was born (discovered) in 1894 in Scotland. Sir William Ramsay, a Scottish chemist, and Lord Rayleigh, an English chemist, discovered me. I was the first of the Noble Gas family to be discovery, (Ya that’s right family I'm number one, what you going to do now). My name, Argon, comes from the Greek word "argos" meaning "inactive," (Argon's symbol is Ar). Like the rest of the family I can get really selfish ( Argon doesn't share ANY of it's valence electrons). If you're every looking for me you will find me in Earth's Atmosphere. You can also find me in area were there is arc weilding going on. My favorite numbers 18 (atomic # is 18). Even though I am one of the most unactive elements in the whole periodic table I don't weigh all that much (Argon weighs 39.948 amu). Unit 3: Atoms and Elements: Classification Lab HI, I am Xenon or the angry one. I was discovered by William Ramsay in 1898 (William Ramsay discovered Xenon in 1898), I know don't say it I'm old. Please don't call me by my greek name Xenos it means "strange" (The greeks called Xenon Xenos wich means Whats the deal with us noble gases being inert I mean I have some buddies Flourine and Oxygen (When they discovered Xenon they said it was inert but in the 1960's they figured out it wasn't inert it rarely combines with other elements like fluorine and oxygen). "strange"). Sorry, I get mad very easily (Xenons boiling point is -108.12 degrees celsius). I get really mad when radon wins hide-and-seek.... well, radon wins all the time,"hmff"!(Xenon is found in the atmosphere 80 parts per billion!). I also get very exited ( Xenon produces a brilliant white light whenit is excited electrically). I am always found next to last, you know what I mean your like so close to winning and then you lose. I Like to hang by metiorites and minerals,(you might find xenon in meteorites and minerals) but my family always remembers at the last second when they are about to forget. Most of all I think I have super powers, you see I can't combust in other words catch on fire (Xenon can't catch on fire). That’s all I have to say about me. Stop looking at me!