Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Isotopes 2-7 October 23 – 24, 2014 Goals Students know Definition of isotope Difference between atomic mass and mass number Students can Calculate average atomic mass The number of protons, neutrons, and mass number when given 2 of the variables Do Now Describe 2 differences between ionic and covalent bonds What is the chemical formula of diphosphorous pentaoxide? What is the chemical formula of magnesium oxide? Do Now Describe 2 differences between ionic and covalent bonds Ionic bonds – metal + nonmetal; valence electrons are taken/given Covalent bonds – nonmetal + nonmetal; valence electrons are shared What is the chemical formula of diphosphorous pentaoxide? P2O5 What is the chemical formula of magnesium oxide? MgO Objective I can calculate the average atomic mass of the isotope candium (Cm) using the Candium Lab analysis. Agenda 1. Do Now, Objective (7 min) 2. Ionic & Covalent Compounds Quiz (10 min) 3. Introduction to Isotopes (15 min) 4. Isotope Whiteboard Problems (10 min) 5. Calculating Average Atomic Mass (10 min) 6. Candium Lab (30 min) 7. Independent Practice Time (10 min) Introduction to isotopes http://www.brainpop.com/science /matterandchemistry/isotopes/ Questions to Consider • What is an isotope? • What isn’t atomic mass an even number? Think pair share: isotopes • How do neutrons keep the protons in a nucleus together? • The neutrons hold the positive protons together like glue in the nucleus Think pair share: isotopes • What does an element’s mass number tell you? Mass number = # of protons + # of neutrons isotope Atoms of the same element with different numbers of neutrons. Example: Two Isotopes of Sodium How are isotopes represented? A: Mass Number: #protons + # neutrons in the nucleus Always larger than Z Z: Atomic number: #protons X: element symbol Isotopes of Sodium 23 11 Na 24 11 Na 2 Ways to write Isotope Symbol Mass Number 23 element symbol 11 Na Atomic number Mass Number Or Sodium-23 # of Neutrons = Mass Number – Atomic Number Class problem Write the isotope symbol for the chemical element that has 6 protons and 8 neutrons (write the symbol both ways) Class Problem Write the isotope symbol for the chemical element that has 6 protons and 8 neutrons (write the symbol both ways) 14 C 6 Carbon-14 Work it Out! Take out Whiteboards and Markers Talk over answer with partner Raise board when directed #1 Write the isotope symbol for the chemical element that has 17 protons and 16 neutrons 33 17 Cl 17p + 16n = 33 mass number or Chlorine-33 #2 How many protons are in the isotope 54Cr? (Chromium-54) 24 (like every atom of Chromium) #3 How many neutrons are in the isotope 42Ca? Mass Number 42 = 20p + ? 22 neutrons #4 How many electrons are in the isotope 23Na? Na has 11 protons, so if its neutral it has 11 electrons 11 electrons Average Atomic Mass the weighted average of the atomic masses of all naturally occurring isotopes of an element. Where do we find the average atomic mass? ON THE PERIODIC TABLE! Average Atomic Mass What is the difference?? The A or ‘Mass Number’ is the mass of that specific isotope The number on the periodic table is the average of all the existing isotopes Isotopes have occur at different rates… Isotope Copper-63 Copper-65 Mass Number 63 65 Percentage Natural Abundance 69.17% 30.83% ABUNDANCE IS HOW OFTEN THAT ISOTOPE OCCURS IN NATURE Steps to finding Average Atomic Mass 1. Convert Percent Natural Abundance to Decimal form (divide by 100) 2. Multiply decimal by Mass Number (for each isotope) 3. Add the product for each isotope together Calculating the average atomic mass Isotope Copper-63 Copper-65 Mass Number 63 65 Percentage Natural Abundance 69.17% 30.83% Step 1: Change the percent abundance to decimals. 69.17%/ 100 = .6917 30.83%/ 100 = .3083 Step 2: multiply the mass number by decimal for each isotope 63 x 0.6917 = 43.577 65 x 0.3083 = 20.040 Step 3: add the product of each isotope together 43.577 + 20.040 = 63.61 amu Quick Write Isotope Rubidium-85 Rubidium-87 Mass Number 85 87 Percentage Natural Abundance 72.2% 27.8% Will the average atomic mass be closer to 85 or 87? Explain your reasoning in a complete sentence. You Try! Isotope Rubidium-85 Rubidium-87 Mass Number 85 87 Percentage Natural Abundance 72.2% 27.8% Step 1: Change the percent abundance to decimals. 72.2%/ 100 = 0.722 27.8%/ 100 = 0.278 Step 2: multiply the mass number by decimal for each isotope 85 x 0.722 = 61.37 87 x 0.278 = 24.286 Step 3: add the product of each isotope together 61.37 + 24.286 = 85.56 amu Candium! Take 2 mins to SILENTLY read the objective and introduction. On your desk Electronic balance A candy Cup – do not eat any now you will have a chance later You will be writing down observations on a separate piece of paper and attaching it to your lab worksheet You will be following the procedure and filling out the data tables on your lab. Candium Procedures 1. Put a piece of paper on your balance and zero it (press ‘tare’) 2. Put all of the candium on the balance and find its total mass (row A, under ‘total’) 3. Count the total number of particles (row B, under total) 4. Put all the plain candium on the balance (row A, 1st isotope) 5. Count the particles of plain candium (row B, 1st isotope) 6. Repeat steps 4-5 with peanut candium (2nd isotope) and peanut butter candium (3rd isotope) 7. Show Ms. Bergman your work to move on to the data analysis section of your lab. Tonight! Complete your isotope homework! Isotopes & Average Atomic Mass Day 2 Do Now Answer all 3 – proficient; 2 – partially proficient; 1 – not proficient Write both isotope symbol for an atom with 5 protons and 7 neutrons - easy How can you find the number of neutrons an atom has using the isotope symbol? - easy Define ‘isotope’ - easy Do Now Write both isotope symbol for an atom with 5 protons and 7 neutrons easy Boron (B) has 5 protons Mass number = 5 + 7 = 12 12 B 5 How can you find the number of neutrons an atom has using the isotope symbol? – easy Mass number – atomic number Boron-12 12 – 5 = 7; 7 neutrons Define ‘isotope’ – easy Atoms of the same element with different numbers of neutrons; for example, Boron-12 and Boron-11 Objectives I can calculate the average atomic mass of the isotope candium (Cm) using the Candium Lab analysis. I can use my understanding of Unit 2- Atomic Structure to complete the Unit 2 Test Review Guide Agenda 1. Do Now, Objective (10 min) 2. Candium Lab Analysis (20 min) 3. Average Atomic Mass Whiteboard Problems (10 minutes) 4. Unit 2 Self-Assessment (5 min) 5. Unit 2 Review Guide Independent Work Time (55 min) Candium Lab Analysis All groups should have completed Data Table 1 Did you label which isotope is which candy? Candium Lab Analysis – Data Table 2 Fill in Data Table 2 using the math in steps 1-5 from your analysis directions. You MUST show all calculations on a separate sheet of paper All calculations must be properly labeled. Example: average mass of candy for the ‘total’ is calculated in step 1, so label it 1a Ms. B’s class calculators may be used – NO PHONES Candium Lab Analysis Questions Questions 6 & 7 should be answered on data table 2 (where labeled 6 and 7 Questions 7 through 10 should be answered on a separate sheet of paper and be properly labeled Use complete sentences Check your lab against the grading rubric to make sure you have everything needed Calculating Average Atomic Mass Whiteboard Problems You need: 1 calculator per table 1 whiteboard per table 1 marker per table Notes Steps to finding Average Atomic Mass 1. Convert Percent Natural Abundance to Decimal form (divide by 100) 2. Multiply decimal by Mass Number (for each isotope) 3. Add the product for each isotope together Whiteboard Problem 1 - easy Isotope Titanium-46 Titanium-47 Titanium-48 Titanium-49 Titanium-50 Mass Number 46 47 48 49 50 Percent Natural Abundance 8.0% 7.8% 73.4% 5.5% 5.3% Calculate the average atomic mass of Titanium Whiteboard Problem 1 - easy Isotope Mass Number Percent Natural Abundance Titanium-46 46 8.0% Titanium-47 47 7.8% Titanium-48 48 73.4% Titanium-49 49 5.5% Titanium-50 50 5.3% Calculate the average atomic mass of Titanium 1. Convert % natural abundance to decimal form (divide by 100) 46 8.0/100 = 0.08; 47 7.8/100 = 0.078; 48 73.4/100 = 0.734; 49 5.5/100 = 0.055; 50 5.3/100 = 0.053 2. Multiply mass number by decimal for each isotope 46*0.08 = 3.68; 47*0.078 = 3.666; 48*0.734 = 35.232; 49*.055 = 2.695; 50*.053 = 2.65 3. Add products for each isotope together 3.68 + 3.666 + 35.232 + 2.695 + 2.65 = 47.923 Whiteboard Problem 1 - medium Uranium is used in nuclear reactors and is a rare element on earth. Uranium has three common isotopes. If the abundance of Uranium-234 is 0.01%, the abundance of Uranium-235 is 0.71%, and the abundance of Uranium-238 is 99.28%, what is the average atomic mass of uranium? Whiteboard Problem 1 - medium Uranium is used in nuclear reactors and is a rare element on earth. Uranium has three common isotopes. If the abundance of Uranium-234 is 0.01%, the abundance of Uranium-235 is 0.71%, and the abundance of Uranium-238 is 99.28%, what is the average atomic mass of uranium? Whiteboard Problem 3 - advanced Complete the table below Whiteboard Problem 3 - advanced Complete the table below Unit 2 Self-Assessment Rate yourself on each of the big concepts from Unit 2. Mark this rating on your Unit 2 Review Guide. A = advanced; P = proficient; PP = partially proficient; U = unsatisfactory 1. Subatomic Particles & Atomic Structure 2. Periodic Table Trends 3. Historic Models of the Atom 4. Electron Configuration 5. Valence Electrons 6. Ionic Bonds 7. Covalent Bonds 8. Isotopes & Average Atomic Mass Unit 2 Review Guide Work independently on completing your Unit 2 Review Guide Work with a friend Start with the hard stuff first Use your notes Ask Ms. B for help Come to the test review sessions Monday/Tuesday/Thursday – lunch Thursday – after school Thursday – before school (7 AM) Unit 2 Review Day – 45 Minutes Goals Check students’ self-assessment scores Students complete key assignments/work that will help them move towards proficient/advance on different individual measures from Unit 2 Do Now Write down 3 things that you WILL DO to prepare for Thursday/Friday’s test on atomic structure. Objective I can use my understanding of Unit 2- Atomic Structure to complete the Unit 2 Test Review Guide Homework Unit 2 Study Guide Agenda 1. Do Now, Objective (7 min) 2. Self-Assessment Check (5 min) 3. Unit 2 Study Guide Independent Practice Time 1. Individual work station 2. Partner work station 3. Small group work station Self-Assessment Look at how you assessed yourself for Unit 2 Concepts earlier in the week. Where do you think your understanding is now? What do you want help from Ms. B with? What do you think you can do by yourself? What do you think you can do in a small group? What do you think you can do with a partner? Independent Work Time You have 3 options today Individual work time – you can do all of the study guide by yourself Partner Work – you can finish the study guide working with 1 partner, you don’t need help other than from each other Small Group – you aren’t sure if you can do all the work. You want to work at stations with other people, and get help from Ms. B throughout the class Independent Work Time Get your materials and go to where you would like to work Expectations No phones No small talk/off-topic discussions Ask for help RIGHT AWAY when you need it – from Ms. B, a friend, the textbook