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CHEM A 2015 Midterm Review Need more practice? Not sure how to study? Reviewing for the Midterm? The following worksheets are organized by learning targets, so you can pick and choose which to complete or do them all! Matter Lab Packet Review: 1. Define each of the following terms: matter: volume: mass: density: 2. Standard metric units: for length and for mass . for volume 3. What is the correct volume as shown on the following graduated cylinders? a. . mL b. . mL a. . g b. . g 4. What is the correct volume as shown on the following balances? 5. A student was told to find the density of a solid object. The mass of the object was found using a balance. The volume was determined using water displacement. Below is the data collected: Volume of water and object in graduate 37.55 mL Volume of water in graduate 31.83 mL Calculate the density of the solid. Mass of object 10.405 g Density of an Unknown Liquid PURPOSE: For Determine what it is by calculating its density. LAB: A student filled a buret with unknown liquid and made sure the original reading of the buret was 0.0 mL. She measured the mass of an empty beaker and then put some of the unknown liquid into the beaker. She recorded the new buret reading and measured the mass of the beaker and liquid. Without emptying the beaker she added more liquid to the beaker. She read and recorded the new buret reading and measured the mass of the beaker and liquid sample. She repeated this process twice more so that she had four values for volume and mass of the unknown liquid. Her data: Sample 1 mass of beaker and liquid mass of beaker mass of liquid Sample 3 39.65g 28.94g ______ mass of beaker and liquid __57.51 g__ mass of beaker __________ mass of liquid __________ volume of liquid (buret reading) 15.20 mL volume of liquid (buret reading) 40.00 mL___ Sample 2 Sample 4 mass of beaker and liquid __51.04 g__ mass of beaker __________ mass of liquid __________ mass of beaker and liquid __62.99 g__ mass of beaker __________ mass of liquid __________ volume of liquid (buret reading) 29.80 mL volume of liquid (buret reading) 49.00 mL Use the grid on the BACK of this sheet to graph the student’s data. Be sure to put scales and labels on each axis and give your graph a title. **Show a neat calculation for the slope of your graph, including labels BELOW: The student was told the unknown liquid was one of the following: cyclobutane (density = 0.720 g/mL) ethanol (density = 0.789 g/mL) 2-octanol (density = 0.822 g/mL). Based upon the data and your calculation, what was the identity of the student’s unknown? Title: Periodic Table Unit Learning Targets Learning Targets 1.1, 1.5 and 1.12 will be assessed on quizzes, but not the unit test. 1.1 I can write the names and symbols of the elements in columns 1A – 4A on the periodic table. 1.5 I can write the names and symbols of the elements in columns 5A- 8A on the periodic table. 1.12 I can write the names and symbols of selected transition metals, lanthanides and actinides (1B-12B) on the periodic table. LT 1.2 I can describe how Mendeleev and Moseley organized the periodic table into groups with similar properties. LT 1.3 I can label and describe the major groups (families) of the periodic table: alkali metals, alkaline metals, transition metals, halogens, noble gases, metals, non-metals and metalloids LT 1.4 I can describe the charge and location of protons, neutrons, and electrons within the nucleus and shells of an atom. LT 1.6 I can calculate the number of protons, electrons and neutrons if given the mass and atomic number of an element. LT 1.7 I can describe the relationship between neutral atoms and ions of the same element. LT 1.8 I can explain the relationship between isotopes of the same element. LT 1.9 I can calculate the number of protons, electrons and neutrons in ions and isotopes of the same element. LT 1.10 I can explain the difference between mass number and average atomic mass. LT 1.11 I can calculate average atomic mass. Fill in the Blanks Review Learning Targets Addressed 1.2 I can describe how Mendeleev and Moseley organized the periodic table into groups with similar properties. 1.3 I can label and describe the major groups (families) of the periodic table: alkali metals, alkaline metals, transition metals, halogens, noble gases, metals, non-metals and metalloids Directions: Fill in the blanks on the right with the information in the chart below. Word List actinide series metal alkali metal metalloid alkaline earth metal Moseley atomic mass noble gas atomic number nonmetal family period group periodic law halogen periodic table lanthanide series transition element 1. ____________________ 2. ____________________ 3. ____________________ 4. ____________________ 5. ____________________ 6. ____________________ Dmitri Mendeleev developed a chart-like arrangement of the elements 7. ____________________ called the __(1)__. He stated that if the elements were listed in order of increasing __(2)__, their properties repeated in a regular manner. He called this the __(3)__ 8. ____________________ of the elements. The arrangement used today, devised by __(4)__, differs from 9. ____________________ that of Mendeleev in that the elements are arranged in order of increasing __(5)__. 10. ____________________ Each horizontal row of elements is called a(n) __(6)__. Each vertical column is 11. ____________________ called a(n) __(7)__, or, because of the resemblance between elements in the same 12. ____________________ column, a(n) __(8)__. In rows 4 through 7, there is a wide central section containing elements, 13. ____________________ each of which is called a(n) __(9)__. Rows 6 and 7 also contain two other sets of 14. ____________________ elements that are listed below the main chart. These are called the __(10)__ and 15. ____________________ the __(11)__, respectively. Each of these elements, as well as those in the first two 16. ____________________ columns at the left end of the chart, is classified as a(n) __(12)__. Each of the elements at the right side of the chart is classified as a(n) __(13)__. Each of the elements between these two main types of elements, having some properties in common with each, is called a(n) __(14)__. Each of the elements in Group 1A is called a(n) __(15)__. Each of the elements in the Group 2A is called a(n) __(16)__. Each of the elements in Group 7A is called a(n) __(17)__. Each of the elements in Group 8A is called a(n) __(18)__. 17. ____________________ 18. ____________________ Directions: 1. Go to mrscrane.wiki.farmington.k12.mi.us 2. Following the links to “Chemistry A” and “Periodic Table Unit” 3. Follow the link to “Groups of the Periodic Table” 4. When you get to the website, read and answer the following questions. 1. How are the families of the periodic table like real life families? 2. What is the definition of a metal? __________________________________________________________________ 3. What is common table salt made of? ____________________________ and _____________________________ 4. What is an unusual property of the alkaline earth metals? ________________________________________ 5. Why don’t noble gases react with other elements? _________________________________________________ 6. What does the world “halogen” mean? ______________________________________________________________ 7. What is the definition of a non-metal? ______________________________________________________________ 8. What is the most reactive element? __________________________ 9. Label the periodic table below with: lanthanide series, actinide series, transition metals, alkali metals, alkaline metals, halogens, noble gases. Basic Atomic Structure Review Learning Target Addressed: 1.4 I can describe the charge and location of protons, neutrons, and electrons within the nucleus and shells of an atom. The periodic table is, in many ways, the world’s greatest cheat sheet. The periodic table lists all of the elements (simple substances that make up more complex materials) like gold, silver, tin, lead and mercury. It also provides lots of information about these elements. The table was created a long time ago by a guy named Dmitri Mendeleev who, probably like you, did not want to memorize tons of information. He organized the elements by mass. That worked pretty well to group elements with similar properties together. Soon after a guy named Henry Moseley realized that each element has a specific number of protons. We call this the atomic number of the element. When he rearranged the periodic table by atomic number the elements grouped into columns with similar properties. Questions: 1. Who created the first periodic table? 2. What is an element? 3. What are the vertical (up and down) columns of the periodic table called? ___________________ 4. What are the horizontal (back and forth) rows of the periodic table called? __________________ 5. Which elements have similar properties, those in the same period or in the same family? _________ 6. How did Mosley improve the organization of the periodic table? What makes up each element? The parts that make up an element are called sub-atomic particles. There are three basic sub-atomic particles that we will talk about in chemistry, they are called protons, neutrons and electrons. Each proton has one positive charge of electricity (+1). Each electron has one negative charge of electricity (-1). Neutrons are neutral, which means they do not have a charge. 7. What is a sub-atomic particle? 8. What is the difference between a proton, a neutron and an electron? Here is a close-up of the periodic table symbol Here is a close-up of the element carbon if we for carbon, an element that is very common and could see it under a very powerful microscope: we will study about this trimester: KEY Atomic Number p = proton n = neutron Mass Number = electron Nucleus 9. Are the protons and neutrons found inside or outside the nucleus? 10. Are the electrons found inside or outside the nucleus? The electron cloud is made of “shells” that hold the electrons. Carbon has 2 shells and is in the 2nd row of the periodic table. 11. How many electrons does carbon have? 12. How many protons does carbon have? 13. How many neutrons does carbon have? 14. What is the total positive charge of carbon? 15. What is the total negative charge of carbon? These + and – charges “cancel out” making a neutral carbon atom. Practice with Ions Learning Target Addressed: 1.7 I can describe the relationship between neutral atoms and ions of the same element. Remember: The charge on an ion will involve a number and a sign. The number will always be the number of electrons involved, e.g., loss of two electrons is +2. The sign will be positive if electrons (negatives) are lost and negative if electrons are gained. I. Determine the following charges 1. An atom having lost three electrons 2. An atom having lost five electrons 3. An atom having gained one electron ________ When you get rid of “negatives” it makes you more positive. Same for atoms! ________ ________ 4. An atom having gained two electrons ________ 5. An atom having lost four electrons ________ II. Determine the charges on the following elements based on their locations on the periodic table. Then circle if each ion is a cation or an anion. 1. oxygen ______ Circle one: CATION or ANION 2. lithium______ Circle one: CATION or ANION 3. boron______ Circle one: CATION or ANION 4. fluorine______ Circle one: CATION or ANION 5. arsenic______ Circle one: CATION or ANION 6. bromine______ Circle one: CATION or ANION 7. xexon______ Why don’t noble gases form cations or anions? III. Fill in the table below: Ion O-2 K+1 N-3 S-2 Sr+2 Al+3 Atomic # Mass # # of protons # of neutrons # of electrons Practice with Isotopes Learning Target Addressed 1.8 I can describe the relationship between isotopes of the same element. Isotopes are atoms of the same element with different masses (or weights) due to different numbers of neutrons in their nuclei. All atoms of the same element must have the same number of protons (and thus the same number of electrons) which is equal to the atomic number. However, atoms of the same element can have different numbers of neutrons and thus a different mass number. The difference in mass does not influence the chemical behavior. Valence electrons are what determine chemical behavior. Hydrogen has three isotopes. The most abundant isotope is ordinary hydrogen-1. A second stable isotope is hydrogen-2 and the third isotope is the radioactive hydrogen-3. The Bohr diagrams for the isotopes of hydrogen are shown below. Notice that only the mass number and number of neutrons are different. Hydrogen-1 Hydrogen-2 Hydrogen-3 K K K 1 2 3 1p 1p 1p 1H 1H 1H 1n 2n 1e 1e 1e 1. What is an isotope? _____________________________________________________________ ___________________________________________________________________________ 2. What does the number next to isotopes signify (ie: Carbon 12 vs. Carbon 13)? _______________ ___________________________________________________________________________ 3. How can you tell isotopes apart in lab? ______________________________________________ ___________________________________________________________________________ 4. Here are three isotopes of an element: 12 6 C 13 6 C 14 6 C a. The element is: __________________ b. The number 6 refers to the _________________________ c. The numbers 12, 13, and 14 refer to the ________________________ d. How many protons and neutrons are in the first isotope? _________________ e. How many protons and neutrons are in the second isotope? _________________ f. How many protons and neutrons are in the third isotope? _________________ 5. Write the symbols for the isotopes of uranium with the following numbers of neutrons: a. 142 neutrons b. 143 neutrons c. 146 neutrons 6. Complete the following chart: Isotope name Uranium-235 Uranium-238 Boron-10 Boron-11 Carbon – 12 Carbon – 14 Tin – 119 Tin – 120 Lithium – 7 Sodium – 23 Atomic # Mass # # of protons # of neutrons # of electrons The Nucleus: Crash Course in Chemistry #1 Learning Targets Addressed: LT 1.4 I can describe the charge and location of protons, neutrons, and electrons within the nucleus and shells of an atom. LT 1.6 I can calculate the number of protons, electrons and neutrons if given the mass and atomic number of an element. https://www.youtube.com/watch?v=FSyAehMdpyI (10:12) The video above should help you answer the following questions: 1. What is “stuff” made of? 2. What are atoms? 3. What are the three sub-atomic particles? 4. What is atomic number AND why is it important? 5. True or False: If the number of neutrons in a silver atom changes, then the atomic number changes. 6. Do all silver atoms have the same number of neutrons? Explain! 7. How to do you calculate the relative atomic mass of silver? 8. What are the masses of the two isotopes (forms) of silver? 9. LABEL mass and atomic number on the chemical symbol of silver to the right: Practice Calculating Average Atomic Mass Learning Target Addressed: 1.11 I can calculate average atomic mass. The atomic masses (or atomic weights) on the periodic table are the average of all the isotopes but it is not a straight average. The atomic masses on the periodic table are the averages of all the isotopes based upon abundance. For example, consider element X: 60% mass 40 amu, 30% mass 42 amu 10% mass 44 amu, then the periodic table mass would be calculated: average mass based upon relative abundance .60 x 40 amu = 24.0 amu .30 x 42 amu = 12.6 amu .10 x 44 amu = 4.4 amu = 41.0 amu Calculate the average atomic mass for the following isotopes. Element Mass of Abundance Atomic Mass Based Upon Relative Abundance Isotope 1. Nitrogen N-14 14.0031 amu 99.64 % N-15 15.0001 amu 0.36 %. 2. Magnesium Mg-24 Mg-25 Mg-26 23.9850 amu 24.9858 amu 25.9826 amu 78.99 % 10.00 % 11.01 % 3. Neon Ne-20 Ne-21 Ne-22 19.992 amu 20.994 amu 21.991 amu 90.51% 0.27% 9.22% 4. Chromium Cr-50 Cr-52 Cr-53 Cr-54 49.9461 amu 51.9405 amu 52.9407 amu 53.9389 amu 4.35 % 83.79% 9.50% 2.36 % Periodic Table Short Answers: 1. Explain how Moseley improved upon Mendeleev’s periodic table. 2. What are the names for groups 1A, 2A, 7A and 8A on the periodic table? 3. Chlorine is a reactive, non-metal that is a gas at room temperature. Predict 2 other elements that would have similar characteristics. 4. Which subatomic particles (protons, neutrons, electrons) affect the mass of an atom? 5. Which subatomic particles affect the charge of an atom? EXPLAIN! 6. What is an ion? Provide both a definition AND an example. 7. What is the difference between a mass number and an average atomic mass? Which is listed on the periodic table of elements? 8. What is an isotope? Provide BOTH a definition AND an example. Atomic Structure Learning Targets 2.1 I can describe how society’s understanding of atomic structure has changed over time. 2.2 I can draw Bohr Diagrams for the first 20 elements. 2.3 I can draw Dot Diagrams for neutral atoms. 2.4 I can create orbital diagrams to show the placement of electrons in suborbitals for the first 36 elements. 2.5 I can create complete electron configurations for the first 36 elements. 2.6 I can create noble gas electron configurations for the first 36 elements 2.7 I can compare and contrast the information provided in Bohr Diagrams, Dot Diagrams and Electron Configurations. Bohr Diagram Practice Learning Target Addressed: 2.2 I can draw Bohr Diagrams for the first 20 elements. Directions: Write Bohr Diagrams for each of the following atoms: aluminum (Al) sulfur (S) oxygen (O) calcium (Ca) Dot Diagram Practice Learning Target Addressed: 2.3 I can draw Dot Diagrams for neutral atoms. 2.7 I can compare and contrast the information provided in Bohr Diagrams, Dot Diagrams and Electron Configurations 1 8 H 2 3 4 5 6 7 Li Be B C N O F He Ne Follow Up Questions: Compare and Contrast Bohr Diagrams and Dot Diagrams. What information do Bohr Diagrams provide that a Dot Diagram does not include? ____________________________________________________________________________________ ____________________________________________________________________________________ Helium has 2 valence electrons and Neon has 8 valence electrons. But what do they both have in common? __________________________________________________________________________________ __________________________________________________________________________________ Extra Notes on Electron Diagrams-Orbitals, Electron Configurations and Noble Gas Configurations Learning Targets Addressed: 2.4 I can create orbital diagrams to show the placement of electrons in suborbitals for the first 36 elements. 2.5 I can create complete electron configurations for the first 36 elements 2.6 I can create noble gas electron configurations for the first 36 elements One way to approach the very abstract task of filling electron orbitals is to use an analogy to make it a bit more concrete. Imagine you are the landlord of a very strange apartment building. Your job is to fill the apartments in the building in the most efficient way possible. You are required by the owner of the building to fill the rooms in a certain way. The rules are summarized in the table on the next page. In the building the different floors are like the different orbitals in an atom. The orbitals are numbered starting from one, just like the floors in an apartment. Each room corresponds to one suborbital: one box on the diagram above. The rooms can hold to more than two electrons (two people) each. In each room only a man and a woman may be paired together. In the strange world of quantum mechanics there are no same-gender room mates. Apartment House Rules Electron Rules From the Bottom Up: Rooms must be filled from the ground Aufbau Principle: the electrons fill the available orbitals floor up. Fill the one room on the first floor before starting to from lowest energy to highest energy. In the ground state all put new tenants on the second floor. Then fill the s room the electrons are in the lowest possible energy level. before the p rooms. At higher floors the order might change a bit. Singles First: the owner of the building wants to have the tenants spread out as much as possible. For that reason singles are placed in rooms before couples. If couples must be placed into a room then all of the other rooms on that floor must already have a single in them. Hund’s Rule: The electrons must be placed into the orbitals in such a way that no pairs are put together unless absolutely necessary. That is, single electrons must be placed into boxes first and then paired up if necessary. Opposite Gender Only: When two people are placed in a room they must be of opposite genders. No men may room together and no women may room together. This is an arbitrary rule on the part of the owners: we all know this isn’t how it works in the real world. Pauli Exclusion Principle: Electrons come in two varieties based on the direction they are ‘spinning’. There is an Up spin and a Down spin. Up and Down spins are always paired together and Up-Up or Down-Down combinations are not allowed. No two electrons can ever be in the same place at the same time. Here is an example of the rooms in the apartment house having been filled in by the rules. The element Sulfur has 16 electrons and starting from the bottom up you place two (1 Up and 1 Down) in the 1s suborbital. Next, electrons are placed in each of the 2p suborbitals until there is one in each suborbital. Then the rest of the electrons are filled into the 2p suborbitals. After that the 3s suborbital is filled and then the 3p. Electrons are placed in the boxes of the 3p suborbitals one at a time until there is one in each suborbital. After that the remaining electron is placed as part of a pair in the first 3p box. The electron configuration of Sulfur is 1s2 2s2 2p6 3s2 3p4. In that notation 1s2 means orbital1, s-type suborbital, 2 e-; 2s2 means orbital 2, s-type suborbital, 2 e-; 2p6 means orbital 2, p-type suborbital, 6 e-; 3s2 means orbital 3, s-type suborbital, 2 e-; and, finally, 3p4 means orbital 3, p-type suborbital, 4 e-. “Reading” the Periodic Table Look at the electron configurations of Oxygen and Sulfur. Notice that in both cases the last 1s2 2s2 2p4 Oxygen suborbitals to fill are p suborbitals. Notice also that there are 2 electrons in an s suborbital and 4 electrons in p orbital for both Oxygen and Sulfur. 1s2 2s2 2p6 3s2 3p4 Sulfur For these reasons Oxygen and Sulfur belong to the p-block of elements in the periodic table. In fact, all of the elements from Groups 13 to 18 are part of the p-block. All of the elements in this block fill a set of p suborbitals last and all of them have their valence electrons in s and p suborbitals. Here you can finally understand the reason that having eight electrons is so important. Each s orbital holds 2 electrons and each p orbital holds 6 electrons. Together they can hold the eight electrons it takes to finish off the suborbitals and make the valence shell full. Other sections of the periodic table are also known by the type of suborbital that fills last in that section. In Groups 1 and 2 the s suborbitals are filling. In Groups 3 through 12 the d suborbitals are the last to be filled. Incidentally, one important fact is that the 4s suborbital fills before the 3d suborbitals start to fill. This is because the 4s suborbital is actually slightly lower in energy than the 3d suborbitals. You will not be much concerned with any suborbitals higher than the 4s suborbital since there are some interesting but complicated exceptions to the rules when it comes to filling the 3d suborbitals. Noble Gas (Abbreviated) Electron Configurations As we get to larger elements we notice the electron configuration becomes tediously long and repetitive so obviously there must be some way to abbreviate configurations. The system for abbreviating involves comparing the electron structure of the atom you are considering with that of a noble gas. Since the noble (or inert) gases have the most stable electron arrangements we use them for a reference. An element is abbreviated by comparing its structure to the noble gas at the end of the preceding period of the periodic table. You abbreviate the element's configuration by indicating the appropriate noble gas plus all of the additional electrons in the element you are considering. Example: Show the abbreviated configuration for chlorine. Note that the noble gas neon precedes chlorine. 35 20 The complete configuration for chlorine is 17 Cl 1s22s22p63s23p5 since neon has the configuration 10 Ne 1s22s22p6 this sequence can be replaced by [Ne], so the abbreviated configuration for chlorine is 35 17 Cl [Ne]3s23p5 Electron Configuration Practice Learning Targets Addressed: 2.5 I can create complete electron configurations for the first 36 elements 2.6 I can create noble gas electron configurations for the first 36 elements Directions: Please write the complete electron configuration AND noble gas configuration for the elements listed below: HINTS!! Use the boxes for arrow orbital diagrams below IF it helps you to create the electron configurations Remember what the largest exponent in each level can be: s = 2 p = 6 d = 10 For noble gas configurations: Put the noble gas before the element in [ ] with the highest s suborbital and anything after that if there is anything. Element (Symbol) Complete Configuration Noble Gas Configuration Sulfur (S) Oxygen (O) Potassium (K) Beryllium (Be) OPTIONAL ARROW DIAGRAMS TO HELP WITH THE CONFIGURATIONS : Atomic Structure Worksheet Learning Targets Addressed: 2.3 I can draw Dot Diagrams for neutral atoms. 2.4 I can create orbital diagrams to show the placement of electrons in suborbitals for the first 36 elements. 2.5 I can create complete electron configurations for the first 36 elements 2.6 I can create noble gas electron configurations for the first 36 elements 2.7 I can compare and contrast the information provided in Bohr Diagrams, Dot Diagrams and Electron Configurations For each element listed you are to draw or write the following: the symbol, the complete electron configuration, the noble gas configuration, the arrow orbital diagram and the dot diagram Nitrogen Symbol Complete electron configuration Arrow orbital diagram Noble Gas configuration Dot Diagram Sulfur Symbol Complete electron configuration Arrow orbital diagram Noble Gas configuration Dot Diagram Helium Symbol Complete electron configuration Arrow orbital diagram Noble Gas configuration Dot Diagram Aluminum Symbol Complete electron configuration Arrow orbital diagram Noble Gas configuration Dot Diagram Phosphorus Symbol Complete electron configuration Arrow orbital diagram Noble Gas configuration Dot Diagram Iron Symbol Complete electron configuration Arrow orbital diagram Noble Gas configuration Dot Diagram Copper Symbol Complete electron configuration Arrow orbital diagram Noble Gas configuration Dot Diagram Arsenic Symbol Complete electron configuration Arrow orbital diagram Noble Gas configuration Dot Diagram Atomic Structure Short Answers 1. Learning Target 2.7 What information does a Bohr Diagram provide that neither a dot diagram nor an electron configuration includes? 2. Learning Target 2.7 Although dot diagrams are easier to write than electron configurations, what extra information does the electron configuration provide? 3. Learning Target 2.7 Why do people often prefer to use noble gas configurations instead of complete electron configurations? 4. Learning Target 2.7 If a nuclear physicist was trying to show the change in the nucleus of an atom during a nuclear explosion, which kind of diagram would he/she most likely use AND WHY? 5. Learning Target 2.7 Which type of diagram would be most useful in order to explain the movement of valence electrons from one atom to another? 6. Learning Target 2.7 Why do we need so many different diagrams of the atom (Bohr, dot, orbital, electron configuration, noble gas configuration)?