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1 Chemistry first quarter Review Outcome Demonstrate experimental design Demonstrate experimental design Name_____________________________________________________Pd______ Sample Question 1. Which instruments are used during a lab investigation for measuring mass, volume and height for the given object 2.Use the table to find the mass of NaCl: Evaporating Dish + lid Evaporating Dish + lid + HCl Evaporating Dish + lid + NaCl 38.5g 43.6g 42.7g Answer Mass- electronic scale, volume – graduated cylinder, height - ruler Mass of NaCl = 42.7 g -38.5g = 4.2 g 1.75 L x 1000ml = 1750 mL 1L How many milliliters are in 1.75L? ( use factor label method) How many Kilograms are in 250 grams? Distinguish between elements and compounds Explain the characteristics of chemical changes Compare the early theories of the atom. Identify subatomic particles of the atom. Describe the discovery of the nucleus by explaining Rutherford's experiment 3. Which of the following is a compound and can be chemically decomposed? A. Na E.MgO B. NaCl C. CCl4 D. Cl 4. What are four clues that indicate that a chemical change has taken place? 5. Give the scientist who is responsible for each model __1. an indivisible sphere with uniform density __2. positively charged atom embedded with electrons __3. a small, dense, positively core with most of the atom empty space __4. small, dense nucleus consisting of protons and neutrons with electrons in levels outside the nucleus 6. Which of these contains most of the atom’s mass 7. Complete the following chart Subatomic location relative charge Particle mass e n p How will you describe a proton? Write three points. 8. What three things did Rutherford observe in his gold foil experiment and what did they tell him about the atom? 250g x 1Kg = .25 Kg 1000 g The correct answer is B, C and E. Elements joined together in a chemical formula make a compound. Na and Cl are elements. They can be chemically decomposed 1. formation of a precipitant, 2. formation of a gas, 3. change in color(or other physical properties) 4. production of heat or loss of heat These indicate that a new substance has been formed with different physical and chemical properties 1. 2. 3. 4. Dalton Thomson Rutherford Bohr (modern) Nucleous Positively charged protons and neutral neutrons are located in the nucleus of the atom. This core contains most of the mass of the atom and is very small, therefore very dense. Electrons (negatively charged) are found outside the nucleus in specific energy levels that can be determined. It would take 2000 electrons to equal the mass of one proton or one neutron. Protons are positively charged , heavy subatomic particles inside the nucleus 1. Most of the alpha particles pass straight through the atom. This told R that they hit nothing. Most of the atom is empty space. 2. A few of the alpha particles (which have a positive charge) were deflected. This told R that the alpha particles passed close to something with a positive charge. The nucleus is positive. 3. A very few alpha particles bounced straight back. This told R that the alpha particles his something that is very massive and very small (very dense). His conclusion is that the atom has a small, dense, positively charged core. We call this the nucleus. Most of the atom is empty space. 2 Compare atomic sizes to macroscopic sizes by using scientific notation Identify atomic number, mass number and isotopes given the number of protons, neutrons and electrons. Multiply and write the answer in their proper significant digits 6.2x 7.81 8.22x 6.0 6.2 x 7.81 = 48.422 = 48 (round off to 2 significant digits) 8.22 x 6.0= 49.32 = 49 ( round off to 2 sig. fic.) 10. a. Determine the number of electrons, protons and neutrons in the following isotopes. 10. a. Element Lithium-7 26 13 Al Li-7 3 4 3 26 13 13 13 13 Al protons neutrons electrons 10 .b.Explain what do you mean by an isotope? Give example. 11. What do you mean by a neutral atom? Write atomic particles in the correct notation and calculate a weighted average of isotopes of an element.. 12. Explain why 1224Mg and 1225Mg are classified as isotopes. 13. Lithium – 7 has an atomic number of 3 and an atomic mass of 7 because A. it has 3 protons and 7 neutrons B. it has 3 protons and 4 neutrons C. it has 7 protons and 3 neutrons D. it has 4 protons and 3 neutrons 10. two atoms are isotopes of each other when they are the same element (same number of protons) but have different numbers of neutrons (different atomic mass). 11. Neutral atom has same number of protons and electrons. 12. Isotopes are the same element because they have the same number of protons, but they have different numbers of neutrons and therefore different atomic masses. 14. Choose which pair below are isotopes of each other 13. B is the correct answer 24 12 Mg A. 25 Mg 12 14. A is the correct answer. B. 24 12 24 Mg C. 1327Al 13 13 Al 27 Si 15.a. 80 35Br # of P D. 13 27Al 24 12 Mg X # of ( P + N) b. 28Ni58 15. Write a symbol like those in the question above and name the element. a) An isotope with 35 protons and 45 neutrons d) An isotope with 28 electrons and 30 neutrons Write atomic particles in the correct notation 16. Use this representation of an atom to tell the number of protons, neutrons and electrons. 14 6 C A. B. C. D. 6 protons, 14 neutrons, 6 electrons 6 protons, 14 neutrons, 4 electrons 6 protons, 14 neutrons, 8 electrons 6 protons, 8 neutrons,6 electrons D is the correct answer The subscript gives number of protons. The superscript gives protons + neutrons. The number of electrons in a neutral atom is the same as the number of protons. 3 Describe the structure of an electron cloud. 17. Write three laws of electron distribution Afbau,s Principle , Pauli,s exclusive Principle and Hund,s Rule 18(a). Which one is the right ground state orbital diagram for sulfur? a. _ Describe the modern views of the atom by comparing Bohr's model to the Quantum Mechanical model. 1s 2s 2p 3s _ _ B is the correct answer 3p B _ _ _ 1s 2s 2p 3s C _ 1s 2s 2p 3s D _ 1s 2s 2p 3s 3p _ Carbon . 3p _ _ 3p 1s Nitrogen 2s 2p 1s __ 2s 2p 18.(b) Draw orbital notation for carbon and Nitrogen Compare an orbit to an electron cloud by describing the location of the electron Explain how the colors of light are related to changes in electron energies by analyzing atomic emission spectra. 19. How many electrons can accommodate in an orbital? 2 electrons can accommodate in an orbital 20. Tell if energy is absorbed or released when A. an electron leaps from a lower energy state to a higher energy state B. an electron falls back from a higher energy level to a lower energy level A. energy is absorbed B. energy is released 21. How is light be produced by exciting electrons with energy? When an electron absorbs energy of certain wavelengths, it leaps to a higher energy state and quickly falls back to the ground state, giving off energy we sometimes see as light. The color of light given off is determined by the amount of energy given off by the electron as it falls to the ground state.. 4 Describe early attempts to organize chemical elements and develop the periodic law by constructing a periodic table. Differentiate between metals, nonmetals and metalloids 22. Mendeleev is given credit for the development of the PT. What is the major difference in the table he developed and the modern periodic table? Mendeleev said that the properties of the elements are periodic if elements are arranged by increasing atomic mass. The use of mass was incorrect as Mendeleev found with the discovery of reversed pairs. Modern periodic law says the properties are periodic (and elements are in the same column if they have similar properties) if the elements are arranged by increasing atomic number. 23. Why did Mendeleev leave gaps in his periodic table? Which of the following pairs have similar properties K and Ca K and Cs K and Sr K and Br When Mendeleev was arranging the periodic table, many elements had not been discovered. Mendeleev left gaps for these missing elements and predicted many of their properties from their location on the periodic table. K and Cs as they belong to same group on PT 24. List some properties of metals and nonmetals. Metals- shiny, conduct heat and electricity, malleable, ductile, react with hydrochloric acid Nonmetals – dull, do not conduct heat and electricity, brittle, do not react with HCl 25. Design a lab to determine the properties of metals and nonmetals. Include Outcome, material list, step by step procedure, data table and conclusion Choose known metals and nonmetals and check the properties above. Include purpose, materials, and data table. Illustrate the number of valence electrons using electron dot structure. 26. An element is located on the right of the periodic table, is dull, brittle, and yellow in color and does not conduct electricity. The element is a A. metal B. nonmetal C. metalloid D. cannot be determined from the description 27. Which of the following in group 16 will have the strongest metallic properties A. O B.Se C.Te D.Po 28. For the given atomic numbers , identify which element is metal, nonmetal , or metalloid a.16 b. 10 c.3 d 14 Metals are shiny, malleable, conduct electricity and heat, are located to the left of the stair step line, and have few electrons that they hold on to loosely. Nonmetals are dull, do not conduct electricity or heat, are brittle, are located to the right of the stair step line, and have 5 or more electrons in the outer level which they hold onto tightly. Metalloids are located on the stair step line (Al and Po are exceptions) and have some properties of metals, some properties of nonmetals. 26. B 27. The correct answer is D. 28. a. nonmetal b. noble gases , nonmetal c. metal d. metalliod . 5 Identify and describe groups and families on the periodic table. Explain periodic trends by analyzing the characteristics of elements on the periodic table. 29. Name the following parts of the periodic table. A. Column 1 (IA) B. Column 2 (IIA) C. Column 17 (VIIA) D. Column 18 (VIIIA) E. Columns 3-12 (IB – VIIIB) F. Elements 57 – 71 G. Elements 89 – 103 H. Vertical columns I. Horizontal rows. 30. Why does ionization energy increase as atomic radius decreases? A. a weaker nucleus means electrons can get farther from the nucleus and the most loosely held electron is easier to remove. B. A stronger nucleus means electrons can get farther from the nucleus and the most loosely held electron is easier to remove. C. A weaker nucleus means electrons are held tighter to the nucleus and the most loosely held electron is harder to remove. D. A stronger nucleus means electrons are held tighter to the nucleus and the most loosely held electron is harder to remove. 31. Explain the reason for the following trends A. decreasing radius size and increasing ionization energy across a period or series B. increasing radius size and decreasing ionization energy down a group or family 32. What do you mean by an ion and what is the relationship between atomic radius and ionic radius? 33. What is the difference in electron activity for metallic properties and for nonmetallic properties? A. metals lose electrons; nonmetals gain electrons B. nonmetals lose electrons; metals gain electrons C. metals react to get 6 electrons in their outer level D. nonmetals react to get 6 electrons in their outer level Describe cations and anions by analyzing their formation. 34. When Ca becomes a ion A. loses 1 electron to have a +1 charge B. loses 2 electrons to have a + 2 charge C. gains 1 electron to have a -1 charge D. gains 2 electrons to have a -2 charge A. alkali metals B. alkaline earth metals C. halogens D. noble gases E. transition elements F. Lanthanide series G. Actinide series H. groups/families I. periods. 30. D is the correct answer. Radius and IE both depend on nuclear strength. The nucleus gets stronger left to right on the PT because more protons pull the electrons tighter. The nucleus gets weaker from top to bottom on the PT because the inner level electrons shield some of the nucleus ‘ pull from the outer level electrons. For metals, chemical reactivity is greatest at the lower left of the PT because metals react by losing electrons and the weaker atoms lose electrons more readily. For nonmetals, chemical reactivity is greatest at the upper right of the PT because nonmetals react by gaining electrons and the stronger nuclei gain electrons more readily. 31. A. The nucleus grows stronger with added protons, pulling the electrons tighter and decreasing radius. It is harder to remove an electron from the more tightly held electrons. B. As you go down a column on the PT, more protons and electrons are added. These electrons are added in increasing energy levels. The electrons in the inner levels shield some of the nucleus’ pull from the outer level electrons. These electrons are able to travel farther from the nucleus. It is easier to remove one of these less tightly held electrons. 32. Atom after losing or gaining electrons becomes an ion. After losing electrons atom becomes Cation and have a smaller radius as compare to its atom. After gaining electrons atom becomes an anion and has a larger radius as compare to its atom. 33. The correct answer is A. Metals have low electronegativity (weak nuclei) and give up electrons to nonmetals with their high electronegativity (strong nuclei). 34. B