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Unit 3: Atomic Theory & Periodicity th Monday, October 24 LEARNING OBJECTIVE A: Atomic Warm-up: Pick up the Learning Targets Highlight the quiz and test dates and copy them into your planner Information 1. State the location & charge of each subatomic particle within the atom 2. Use the periodic table to determine the number of protons, neutrons, and electrons Independent Practice #1 is in an atom of an element due on 10/27 3. Define atomic number as it relates to subatomic particles Video Take careful notes on the video, think about the learning targets as you are watching Video Wrap up •What are the 3 common particles in an atom? •What 2 particles are in the nucleus? •If an atom were expanded to the size of a stadium what size would the nucleus be? •What’s between the atom’s nucleus and the electrons? •Where is the majority of the mass in an atom? In your notes Make a table in your notes to complete with the information you have learned. Particle Location in atom Charge Mass in AMU BOHR MODEL A Bohr Model is a simplified version of what an atom looks like. The protons and neutrons are located in the nucleus and the electrons are in “shells” or rings around the nucleus You draw a Bohr Model by placing two electrons maximum in the shell closest to the nucleus and a maximum of eight electrons in each of the other shells. Check in •How many protons does Iodine (I) have? •How many protons does Tungsten (W) have? •Which subatomic particle has a negative charge? •What is the mass of one neutron? •Where in an atom are electrons located? •Draw a Bohr Model of a neutral atom of Sodium (Na) Information from the Periodic Table Number of Protons: same as atomic number Mass Number: listed as an AVERAGE on the periodic table. Calculated as number of protons plus the number of neutrons for individual atoms. Number of electrons in a neutral atom: same as number of protons Isotope/Atomic Notation: Tuesday, October 25 LEARNING OBJECTIVE A: Atomic Information Warm-up: How many protons does Bromine (Br) have? How do you know? Write the atomic/isotope notation for Bromine-81 Independent Practice #1 is due on Friday 10/27 Answer to Warm-up Warm-up: 1. How many protons does Bromine (Br) have? 2. How do you know? 3. Write the atomic/isotope notation for Bromine-81 Answer: 1. Bromine has 35 protons 2. The atomic number for Bromine is 35. The atomic number is equal to the number of protons. 3. The isotope/atomic notation is: Isotopes Each table will need a sheet of Model 1 and each member of your group will need their own Isotopes packet and a periodic table. Choose your roles. Facilitator will appoint a reader for the activity. Spokesperson will appoint a clean up person for the activity. Work through carefully, making sure you reach consensus on each question. Switch your cup to yellow at stop signs (pretend they are yield signs ) but keep moving. Wednesday, October 26 LEARNING OBJECTIVE I will be able to calculate average atomic mass. 1. WARM UP How many neutrons are in… 2. What are isotopes? A. B. C. Uranium-235 (atomic number 92) Lead-207 (atomic number 82) Hydrogen-3 (atomic number 1) Check in from Tuesday today Relative Abundance Lab Wednesday 10/26 Exit Slip Learning Objective I will be able to calculate average atomic mass. Exit Questions Why is average atomic mass so important it was included in the periodic table? Thursday - October 27 Learning Objective B: Isotopes and Relative Atomic Mass Connecting back to Learning Objective A- Atomic Information & Moles and Mass! Warm-up: Have Independent Practice Number 1 out REMINDER: Quiz 1 is TOMORROW Average Atomic Mass How do we calculate average atomic mass using abundancy? 1. The average atomic mass of nitrogen is 14.0067 amu. Predict which isotope listed below is most abundant in nature Wrap Up ◦ a. Nitrogen-13 ◦ b. Nitrogen-14 ◦ c. Nitrogen-15 2. A certain element was originally named “muriaticum” by its discoverer. This element exists on Earth as a mixture of two isotopes. The most abundant isotope (75.76%) has a mass of 34.9689 amu; the other isotope (24.24%) has a mass of 36.9659 amu. Calculate the average atomic mass and identify the element by its modern name. Table Swap Each table has a specific learning goal listed. Your group will be solving and writing questions around the learning goal you have been assigned. We will rotate (Table 1 Table 2 Table 3 … etc) every 4 minutes There is a starter problem on the table for your group to solve – you must show all your work! Once you have solved the problem you need to write a similar type of problem for the next group. Include the answer so they can check their work. Answers 1.B Nitrogen-14 1.(0.7576)(34.9689 amu) + (0.2424)(36.9659) = 35.45 amu Chlorine Friday – October 28 Learning Target C: Half-Life Independent Practice #2 is Due Tuesday 11/1/16 Warm-up: Be ready for the quiz! You will have 15 minutes to take the quiz Quiz Clear your table of everything except something to write with, a calculator, and a periodic table. When you are done – pick up independent practice #2 from the front table. Independent Practice #2 is Due Tuesday 11/1/16 Monday, st October 31 Today you will work on a half-life lab 1. Complete the first page of the lab as a pair. (2 per table) 2. Graph your data. Compare with the other pair at your table. 3. Work together through the first handout. 4. Get the second portion (everyone has their own) and work through them as a group. Monday, st October 31 Target C: Half-Life Warm-Up: Have your half-life extension problems from Friday out and some note paper out to take notes on Plan for today – Monday 10/31 Review Quiz #1 Half-Life Calculations & Practical Examples Begin talking about fission & fusion Tuesday November st 1 Fission & Fusion Learning Targets ◦I can compare the energy outputs of fission and fusion reactions ◦I can compare the energy outputs of fission and fusion to other energy transformations Warm-Up: A specific radioisotope takes 600 minutes to decay to 12.5% of its original mass. What is its half life? Plan for today – Tuesday 11/1 Review half-life Fission & Fusion handout (complete) Discussion Independent Practice #2 Review for Wednesday Quiz Nuclear Reactions – some rules for fission & fusion 1. Mass must be conserved: atomic mass of the reactants must be equal to the atomic mass of the products 2. Protons must be conserved: the total number of protons that go into the reaction (on the reactant side) must be the same total number that comes out of the reaction (on the product side) 3. If the atomic number of an element changes, the element itself changes Fission & Fusion (from your note packets) Fission: Fusion: A large nucleus is hit by something and splits into many smaller nuclei Two smaller nuclei are combined to make a larger nucleus Usually Uranium-235 is hit by a neutron Recognizable because the largest mass will be on the Recognizable because the largest reactant side of the mass will be on the reactants equation. side of the equation Fission Wednesday November nd 2 Warm- Up: Clear your table for the Quiz, you need a periodic table, a calculator maybe, and something to write with Independent Practice #3 Due Monday 11/7 Learning Target D: Electron Configuration Boarding House Model What do the symbols mean? = A person = Bunk bed for 2 people The big number (1, 2, 3) = The floor number s = The sunny room p = The pink room The exponents (1,2,3,4,5,6) = How many people are in that room on that floor Rules for filling the boarding house (generated by our class) 1. Start adding people on the lowest floor first 2. 2 people can fit in each bunk bed 3. You can not put someone in a top bunk until all of the bottom bunks in that room are full 4. No one can sleep in the kitchen 5. You must fill all the bunk beds on the current floor before you can move to the next highest floor 6. Sunny room on that floor must be filled before pink room on that floor 7. People are added gradually, no one leaves 8. Add people from left to right in the room What is the manager code for these three situations? A B C Thursday November rd 3 Learning Target D: Electron Energy Levels Warm-up: Write the managers code for the following boarding house Warm-up Solution What do these symbols represent? What do these symbols represent? Orbital (a bunk bed) A single electron spinning up (one person) Two electrons with opposite spins (two people – one in bottom bunk one in top bunk) A sublevel (a room) Electron configuration (managers code) Orbital Diagrams & Electron Configurations Orbital Diagrams o Explain how electrons are arranged within the atom o Show the order in which electrons are placed in orbitals o Use boxes to represent orbitals Electron Configuration Short hand to show how many electrons are in an atom and at which energy level they will be found. Electrons in Orbital Diagrams To place electrons in orbital diagrams, electrons: oare represented by arrows and the direction of the arrow is used to represent electron spin ofill orbitals in order of increasing energy beginning with 1s, then 2s and 2p, then 3s and 3p Electrons in Orbital Diagrams Orbitals can hold a maximum of two electrons. Within sublevels that contain multiple orbitals, one electron is placed in each orbital with parallel spins before the electrons are paired. Electron Configurations Chemists use a notation called the electron configuration to indicate placement of electrons in an atom. The lowest energy sublevel is written first, then sublevels with increasing energies. The number of electrons in each sublevel is written as a superscript. Period 1: Hydrogen and Helium The 1s is written first; it has the lowest energy. Period 2: Lithium to Neon Period 2 begins with lithium, which has three electrons, 1s2 2s1. After the 2s is filled, the 2p orbitals are filled. One electron is placed in each p orbital before they are paired. An abbreviated configuration uses a noble gas in brackets to represent the filled electron configuration of that noble gas. [He] 2s1 Period 2: Lithium to Neon Period 2: Lithium to Neon Guide to Drawing Orbital Diagrams Sample Problem Draw the orbital diagram for nitrogen. Step 1 Draw boxes to represent the occupied orbitals. Nitrogen has an atomic number of seven, which means it has seven electrons. Draw boxes to represent the 1s, 2s, and 2p orbitals. 1s 2s 2p Sample Problem Draw the orbital diagram for nitrogen. Step 2 Place a pair of electrons in the last occupied sublevel in separate orbitals. We place the remaining three electrons in the 2s orbitals. 1s 2s 2p Sample Problem Draw the orbital diagram for nitrogen. Step 3 Place remaining electrons with opposite spins in each filled orbital. First we place a pair of electrons with opposite spins in the 2p orbitals, with arrows in the same direction. 1s 2s 2p Period 3: Sodium to Argon [Ne] is used to represent 1s2 2s2 2p6. Period 3: Sodium to Argon Learning Check Draw the abbreviated orbital diagram for aluminum: [Ne] 3s2 3p1 Solution Draw the abbreviated orbital diagram for aluminum, [Ne] 3s2 3p1. 1. The preceding noble gas is Ne; we use this to represent 1s2 2s2 2p6. 2. Fill the 3s, and add the last electron to the 3p sublevel. [Ne] 3s 3p Friday, November 4th Learning Target E: Ions Guiding Question: How are ions made from neutral atoms? Warm-up: Write the ground state electron configuration for a neutral atom of Chlorine Warm-up Solution Chlorine has 17 electrons in a neutral state (atomic number of 17 = 17 protons, to be neutral it would need 17 electrons) Ground state electron configuration for a neutral atom of Chlorine: 1s22s22p63s23p5 or [Ne] 3s23p5 How should I check my work? Each s sublevel can only have two electrons Each p sublevel can only have a maximum of 6 electrons The exponents should add up to 17. Chlorine is in the 3rd row of the periodic table and the p5 column so the electron configuration should end in 3p5 What is an ion? An ion is a charged particle. Instead of being neutral, our ion has either a positive or a negative charge Ions are formed when atoms gain or lose electrons. Positive ions are called cations. They are formed when a neutral atom loses electrons. Negative ions are called anions. They are formed when a neutral atom gains electrons. Metallic atoms tend to lose electrons to form positive ions/cations. Nonmetallic atoms tend to gain electrons to form negative ions/anions. How do we calculate the charge on an ion? The charge on an atom or ion is equal to its number of protons minus its number of electrons Charge = (# of Protons) - (# of Electrons) Example: An atom with 17 protons and 18 electrons has a charge of -1 Cl1- How do we indicate that an element is in its ion form? Charge is listed on the top right side of the atomic/isotope notation: Cl1Ion configuration includes the gained or lost electrons For an ion of chlorine the ion configuration would be: 1s22s22p63s23p6 or [Ne] 3s23p6 or [Ar] Ionization wrap up Ionization is losing or gaining electrons to get to a full valence shell. If an element has less than 4 electrons in the valence it will lose electrons, if it has more than 4 electrons it will gain electrons. This is called the octet rule. Elements want to have 8 valence electrons Oxidation & Reduction If an element loses electrons it is OXIDIZED If an element gains electrons it is REDUCED LEO the lion says GER LEO= Loss of Electrons is Oxidation GER= Gain of Electrons is Reduction Monday November 7, 2016 Learning Target: Electron Dot Diagrams & Ion Configuration Warm-up: How many valence electrons does a neutral atom of Nitrogen-15 have? How do you know? Warm-up Warm-up: How many valence electrons does Nitrogen have? How do you know? How many ways can you show that Nitrogen has 5 valence electrons? 1. Bohr Model 2. Orbital Diagram 3. Electron Configuration 4. What group it is in on the periodic table Ionization – review from Friday Ionization is losing or gaining electrons to get to a full valence shell. If an element has less than 4 electrons in the valence it will lose electrons, if it has more than 4 electrons it will gain electrons. This is called the octet rule. Elements want to have 8 valence electrons Oxidation & Reduction If an element loses electrons it is OXIDIZED If an element gains electrons it is REDUCED LEO the lion says GER LEO= Loss of Electrons is Oxidation GER= Gain of Electrons is Reduction The ion charges that form are called “oxidation states” For Today Finish Electron Configuration, Ions, Subatomic Particle Review Independent Practice #3 Start Lewis Dot Diagrams Tuesday, November th 8 Plan for today: Quiz #3 Lewis Dot Diagrams Pick up Independent Practice #4 Due 11/19 Quiz Clear your table except for a periodic table, something to write with, and a calculator. You will have 15 minutes for the Quiz. SHOW ALL YOUR WORK. Reminder for Throwback question - the formula for Molarity (concentration) is: Molarity = moles / liters Lewis Dot Diagrams Work through the Lewis Dot Diagrams activity as a group, checking in frequently to make sure you have reached a consensus. When you are finished please gather the Lewis Dot Diagram (Dot Diagram #2) handout from the front. One per group. Cut out the elements and distribute them evenly among your group members. Write the dot diagram configuration for all of them. When you are done, look for patterns in the diagrams by organizing them as a group. What do you notice? Wednesday November th 9 Learning Target: Trends in Reactivity You will need goggles, something to write with, your notes, and the lab handout. New Vocabulary: Group & Period On your periodic table you have Groups & Periods the horizontal rows are called periods (energy levels) the vertical columns are called groups (families) The main groups are numbered from 1A to 8A going from left to right The block in between Group 2A and Group 3A is where the transition metals are placed Why does this matter? Elements in the same group have similar chemical properties – however, their reactivity can vary. Your lab today will help you to answer the question: How does the position of an element in a column on the periodic table affect the reactivity of that element? Lab Write your hypothesis to answer the testable question Perform your experiments to test your hypothesis (you might want to use a flashlight to see the reaction better!) Record your data (you should see a minimum of 4 reactions) Write up your procedure and your conclusion Due tomorrow: procedure, data, conclusion (1 per group) Thursday November th 10 Properties of Elements – you will need a jacket if you do not have one, we’re going outside near the end of class. Monday - November 14 Learning Target H: Discuss the properties of Alkali Metals Learning Target G: Describe the trend in atomic radius as you move from left to right and top to bottom of the periodic table Warm-up: Draw the Lewis Dot Diagrams for the following metals: ◦Lithium ◦Sodium ◦Potassium Some new terms! Ionization Energy: The amount of energy needed to remove an electron from an atom First Ionization Energy: The amount of energy needed to remove the MOST loosely held electron from an atom in its ground state Electronegativity (sometimes called Electron Affinity): The energy change for the process of adding an electron to an atom. How much an atom would like to gain an electron. Atomic Radius: Distance from the nucleus to the outermost energy level (valence electrons) Properties of Groups Poster Your table group will make a poster that explains the properties of 1 of the periodic groups. Your poster should have: The name of the group The number of the group How many valence electrons elements in the group have What elements make up the group At least one fact about the group Trends in atomic radius, electronegativity, and first ionization energy The atomic radius, electronegativity, and first ionization energy of your FIRST element in the group At the end of the class we will rotate around and complete our notes using the posters Learning Target: Define the terms “period” and “group” as they relate to the periodic table Plan for Today Pick up and complete the periodic table handout from the front of the class 1a & 2a Periodic Table Groups - Alkali Metals - Group 1 Alkali metals are elements found in group 1 of the Periodic Table. Alkali metals are soft, malleable, ductile, and are good conductors of heat and electricity. They have Low melting and boiling points compared to most other metals. The names of these elements are Lithium, Sodium, Potassium, Rubidium, Cesium and Francium. They are silvercolored when pure and soft. Elements classified as Alkali Metals are very reactive metals that do not occur freely in nature. Periodic Table Groups - Alkaline Earth metals - Group 2 Alkaline Earth metals are the elements in group 2 of the Periodic Table. The chemical symbols identify the element names. The alkaline earth metals are silvered colored, soft metals. Elements classified as Alkaline Earth Metals are all found in the Earth’s crust, but not in the elemental form as they are so reactive. Instead, they are widely distributed in rock structures. Alkaline metals are usually shiny solids that conduct heat or electricity and can be formed into sheets. 7a & 8a Periodic Table Groups - Halogens - Group 7a The 5 elements classified as "Halogens" are located in Group 7a of the Periodic Table. They are non-metals with low melting and boiling points. They have colored vapors and are poor conductors of heat and electricity. The elements classed as Halogens are Fluorine, Chlorine, Bromine, Iodine and Astatine. Periodic Table Groups - Noble Gases - Group 8a The Noble Gases are in Group 8a of the periodic table. All of these gases are found in air and make up around 0.96% of the atmosphere. They are very unreactive and colorless gases The 6 elements classed as noble gases are Helium, Neon, Argon, Krypton, Xenon and Radon. Tuesday November 15 Learning Target: Periodic Trends – atomic radius, valence electrons, electronegativity, ionization energy Warm-up: Write the electron configuration for a neutral atom of Carbon. Circle the final orbital notation in your configuration. Example: The electron configuration for a neutral atom of sulfur is: 1s22s22p63s23p4 Periodic Trends Orbital Notation & The Periodic Table ◦ Assessment #1 ◦ If correct Go on to Coulombic Attraction ◦ If not yet correct Electron Configuration Practice Sheet Coulombic Attraction ◦ Assessment #2 ◦ If correct Go on to Periodic Trends ◦ If not yet correct Review Coulombic Attraction, write a list of rules for identifying strength of Coulombic attraction Periodic Trends (model 1 is a separate sheet – make sure you get both ) During each activity: ◦ Use the post-it notes in your pencil boxes to make a claim, provide evidence, and list a scientific reason for the 4 periodic trends we are discussing today. ◦ A sample claim format has been listed on the board for you! ◦ Each group should make at least 1 claim, 1 evidence, and 1 reason to place on the poster on the front table. That is 3 post-it notes total Wednesday 11/16 Guiding Question: What is the scientific reasoning for the trends found on the periodic table? Goal: Complete all three assessments Turn in assessments and completed independent practice by the end of class Prepare for tomorrow’s quiz What trends did we observe on the periodic table? A trend must be explained both across a period on the periodic table (from left to right on the row) and down a group on the periodic table (from top to bottom on a column) We observed trends in: •Atomic Radius •Electronegativity •Ionization Energy •Reactivity •Orbital Notation Trend in Atomic Radius Atomic Radius increases as you move down a group and decreases as you move (L-R) across a period (in general) Why? Coulombic Attraction! Adding energy levels (electron shells) on to the atom increases its size so as you move down a group, each energy level increases the radius of the atom. When the energy level stays the same (across a period) more protons are added and attract the valence electrons closer to the nucleus, this decreases the radius. Trend in Electronegativity Electronegativity decrease as you move down a group and increases as you move (L-R) across a period (except Nobel Gases) Why? Atomic Radius! Sort of! Simplified version : Increased atomic radius makes it harder for the atom to attract electrons. As the radius increases, the electronegativity decreases. As the radius decreases, the electronegativity increases because the atom is more able to attract electrons. Trend in Ionization Energy Ionization Energy decrease as you move down a group and increases as you move (L-R) across a period (except Nobel Gases) Why? Atomic Radius! Sort of! Simplified version : Increased atomic radius makes it harder for the atom to hang on to its electrons. As the radius increases, the ionization energy decreases. As the radius decreases, the ionization energy increases because the atom is more able to hang on to its electrons and it takes more energy to remove them. Trends in Reactivity For metals, we observed that reactivity increases as you move down a group and decreases as you move (L-R) across a period. For nonmetals, we observed that reactivity decreases as you move down a group and increases as you move (L-R) across a period. Why? Metals want to donate their electrons, so their reactivity is based on ionization energy. Lower ionization energy means more reactive. Non-Metals want to gain electrons, so their reactivity is based on electronegativity. Higher electronegativity means more reactive. Orbital Notation When writing electron configurations for neutral atoms, the final orbital notation will align with the element’s location on the periodic table. Coefficient = period number for s & p OR period minus 1 for d OR period minus 2 for f. Letter = block of the table Exponent = column in that block Example: Gallium : 1s22s22p63s23p64s23d104p1 the final orbital notation is: 4p1 So Gallium will be found in the 4th period (row) in the first column of p-block Thursday November 17 After the Quiz Get your goggles and a lab printout! Read through the lab printout and have a separate sheet of paper out for your observations and answers to the questions. Flame Test Lab Just as a fingerprint is unique to each person, the color of light emitted by an element heated in a flame is unique to each element. When a substance is heated in a flame, the atoms absorb energy from the flame. This absorbed energy allows the electrons to be promoted to excited energy levels. From these excited energy levels, the electrons will eventually drop down to their original energy level. When an electron drops from a higher energy level to a lower energy level, a particle of light called a photon is emitted. The energy of the photon determines the color of the flame that you can observe. Because each element has a different spacing of electron energy levels (or shells), the possible color of flames that can be emitted are unique to each substance. Flame Test Lab In this experiment you will observe the light signature of 6 different samples. Once you have observed the samples you will use the data you collected to identify an unknown sample. Possible Samples Calcium Chloride Copper (II) Chloride Cobalt Chloride Potassium Chloride Barium Chloride Strontium Chloride CaCl2 CuCl2 CoCl2 KCl BaCl2 SrCl2 Friday November 18 Learning Target: Periodic Trends – Claim, Evidence, Reasoning Plan for today: ◦Claim, Evidence, Reasoning ◦Work on Study Guide! Upcoming Dates: Exam on Tuesday November 22nd Study Guide Due Tuesday November 22nd Claim. Evidence. Reasoning. Claim A statement that you believe to be true. “As you go down a group on the periodic table, the number of valence electrons stays constant. As you go across a period on the periodic table, the number of valence electrons increases.” Evidence Evidence: How do you know? A statement that supports your claim. In the group 1A elements, Lithium, Sodium, Potassium, and Rubidium all have one valence electron. In period 2, Lithium has 1 valence electron, Beryllium has 2, Aluminum has 3, Silicon has 4, and Phosphorous has 5. Reasoning Reasoning: Explain your claim and evidence with scientific fact. When you move across a period on the periodic table, the atomic number increases by 1. This increases the proton number by 1, and for the atom to be neutral, it also increase the electron number by 1. Once you get to the end of the period where the noble gas is located, the valence shell is full and another has to be added. In the next period you restart with a new valence shell with 1 electron and the pattern continues. Tuesday November nd 22 Exam Day! Hooray! Please separate your chairs so that there are no more than 2 at each table Clear your table of everything except: ◦ Study Guide ◦ Something to write with ◦ Calculator