Midterm Review 2013-2014 A. Matching Match each description in Column B with the correct term in Column A. Write the letter of the correct description on the line. Column A Column B 1. error a. a measure of the pull of gravity on a given mass 2. precision b. concerned with the reproducibility of measurements 3. 1 liter c. a ratio of equivalent measurements 4. temperature d. originally defined as the mass of 1 L of water at 4C 5. density e. a way to analyze and solve problems, using the units of a measurement 6. conversion factor f. the ratio of the mass of an object to its volume 7. dimensional analysis g. the degree of hotness or coldness of an object 8. weight h. closeness of a measurement to the true value 9. 1 kilogram i. difference between the experimental value and the accepted value 10. accuracy j. the volume of a cube 10 cm on each edge B. Multiple Choice Choose the best answer and write its letter on the line. 11. How many significant figures are in the measurement 2103.2 g? a. 2 c. 4 b. 3 d. 5 12. Which of these equalities is not correct? a. 100cg = 1 g c. 1 cm3 = 1 mL b. 1000 mm = 1 m. d. 10 kg = 1 g 13. How many of the zeros in the measurement 0.000 040 200 m are significant? a. 2 c. 7 b. 3 d. 8 70 Core Teaching Resources Name Date 14. How many milligrams are in 2.5 kg? a. 2.5 × 106 mg b. 25 mg. Class c. 2.5 × 10–4 mg d. 2.5 × 102 mg. 15. The closeness of a measurement to its true value is a measure of its: a. usefulness. c. accuracy. b. precision. d. reproducibility. 16. Which of these measurements is expressed to three significant figures? a. 0.070 mm c. 7007 mg b. 7.30 ×10–7 km d. 0.007 m 17. A metric unit of volume is the: a. L. b. mg. c. km. d. K. 18. The number of seconds in a 40-hour work week can be calculated as follows: 60 min 60 s 1 min 1h = = a. 60 s c. 40 h 60 s 60 min 1h 1 min 1 min 40 h 60 min 60 s = = b. 1 s d. 40 h 60 s 60 min 40 h 60 min 19. The metric prefix kilo- means: a. 100 times smaller. b. 1000 times larger. c. 1000 times smaller. d. 100 times larger. 20. What is the volume of 60.0 g of ether if the density of ether is 0.70 g/mL? a. 86 mL c. 2.4 × 10–2 mL –2 b. 1.2 × 10 mL d. 42 mL. 21. The temperature reading of –14C corresponds to a Kelvin reading of: a. 297.6 K c. 287 K. b. –287 K. d. 259 K. 22. Concentrated hydrochloric acid has a density of 1.19 g/mL. What is the mass, in grams, of 2.00 liters of this acid? a. 2.38 × 103 g c. 4.20 × 10–4 g b. 2.38 g d. 4.20 × 10–4 g 23. A conversion factor: a. is equal to 1. b. is a ratio of equivalent measurements. c. does not change the value of a measurement. d. all of the above 24. Chlorine boils at 239 K. What is the boiling point of chlorine expressed in degrees Celsius? a. 93°C c. –61°C b. 34°C d. –34°C 25. A student measures a volume as 25 mL, whereas the correct volume is 23 mL. What is the percent error? a. 0.087% c. 0.92% b. 8.7% d. 8.0% Chapter 3 Scientific Measurement 71 Name Date Class C. True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 26. Precise measurements are also accurate measurements. 27. Zeros in a measurement are significant. 28. In converting between units, it is necessary to use more than one conversion factor. 29. When converting complex units, you should check that the units cancel, the conversion factors are correct, and the answer has the correct units. 30. The weight of an object changes with its location. 31. A kilogram is the mass of 1 mL of water at 4°C. 32. The density of a substance decreases at its temperature increases. 33. Heat transfers from objects at high temperatures to objects at low temperatures. 34. To convert density from g/cm3 to kg/m3, one of the conversion factors you could use is mg3/kg. D. Problems Solve the problems in the space provided. Show your work. 35. A cube of gold-colored metal with a volume of 64 cm3 has a mass of 980 g. The density of pure gold is 19.3 g/cm3. Is the metal pure gold? 36. Perform the following operations. Make sure that your answers have the correct number of significant digits. a. 4.15 cm × 1.8 cm b. 13.00 m – 0.54 m c. (1.7 × 10–5 m) × (3.72 10–4 m) 72 Core Teaching Resources Name Date Class 37. Calculate the density of a liquid that has a mass of 14.0 g and a volume of 18.0 cm3. E. Essay Write a short essay for the following. 38. Explain how density differs from volume. A. Multiple Choice Choose the best answer and write its letter on the line. 1. Identify the activity that belongs in the field of chemistry. a. developing medicines c. production of a new plastic b. analysis of a compound d. all of the above 2. Which of these chemicals is definitely inorganic? a. one that is made of carbon and hydrogen b. one that is made of nitrogen and carbon c. one that is made of nitrogen and hydrogen d. one that is made of carbon and oxygen 3. Which of the following is not a step for solving a numeric word problem? a. calculate c. analyze b. conclude d. evaluate 4. Identify the false statement. a. Chemistry plays an important role in efforts to increase the world's food supply and to protect crops. b. Biodiesel is a fossil fuel. c. Potato plants with a jellyfish gene will glow when they need to be watered. d. Chemists are working to develop more pest-resistant and disease-resistant plants. 5. A hypothesis is a. an observation recorded from an experiment. b. a proposed explanation for what is observed. c. a summary of the results of many experiments. d. a well-tested explanation for many observations. 6. Which of the following is not a part of the scientific method? a. experimenting c. proving b. observing d. hypothesizing 7. Identify the false statement. a. A scientific law fully explains a set of observations. b. The scientific method is a logical, systematic approach to the solution of a problem. c. For the results of an experiment to be accepted, the experiment must produce the same results no matter how many times it is repeated. d. The scientific method is repeated until a hypothesis either fits all the observed experimental results or the hypothesis is discarded. Chapter 1 Introduction to Chemistry 21 Name Date Class 8. Which of these steps of the scientific method involves stating a relationship but not proposing an explanation for the relationship? a. observation c. theory b. scientific law d. hypothesis B. Questions Write your answer in the space provided. 9. Define chemistry. 10. List the major steps in the scientific method and describe each briefly. A. Matching Match each description in Column B with the correct term in Column A. Write the letter of the correct description on the line. Column A 1. a physical blend of two or more components 2. the change of one or more substances into new substances 3. amount of matter that an object contains 4. a homogeneous mixture 5. a substance that can be separated into simpler substances only by chemical means 6. the simplest form of matter that has a unique set of properties 7. depends on the type of matter in a sample 8. matter that takes both the shape and the volume of its container 9. matter that has a uniform and definite composition 10. a quality or condition of a substance that can be observed or measured without changing the substance’s composition Column B g. physical property a. solution h. mass b. element i. mixture c. substance j. compound d. chemical reaction e. gas f. intensive property B. Multiple Choice Choose the best answer for each question and write its letter on the line. 11. Another name for homogenous mixture is a. solution. c. element. b. matter. d. mass. 12. The chemical symbol for iron is: a. Ir. c. Fe. b. FE. d. I. 13. Which of the following is a physical property? a. color c. freezing point b. hardness d. all of the above 48 Core Teaching Resources Name Date Class 14. Which of the following statements describes a solid? a. It takes the shape of its container. b. It takes the volume of its container. c. Its particles are packed together tightly. d. It is easily compressed. 15. At room temperature, which of the following is typically in a physical state different from that of the other three? a. water c. grape juice b. milk d. oxygen 16. Which term does not fit with the others listed? a. ice c. salt b. steam d. water 17. Which of the following is an example of a physical change? a. toasting bread c. digesting a banana b. cooking a hamburger d. melting butter 18. An example of a heterogeneous mixture would be a. sugar. c. tap water. b. salt water. d. vegetable soup. 19. Which of the following is a compound? a. carbon b. hydrogen c. oxygen d. water 20. Iron is an example of a(n) a. element. b. compound. c. heterogeneous mixture. d. homogeneous mixture. 21. The element whose chemical symbol is C is a. calcium. c. copper. b. carbon. d. chlorine. 22. Which of the following events can best distinguish a physical change from a chemical change? a. Energy is absorbed or released. c. A gas is produced. b. a different chemical composition d. Mass is conserved. 23. Which of the following is an example of a chemical change? a. cooking meat c. dissolving sugar in iced tea b. slicing cheese d. freezing water C. True-False Classify each of these statements as always true (AT), sometimes true (ST), or never true (NT). 24. In a chemical reaction, mass is neither created nor destroyed; it is conserved. 25. Dissolving salt in water is a chemical change. Chapter 2 Matter and Change 49 Name Date Class 26. Physical changes are not easily reversed. 27. Elements can be separated into simpler substances by chemical reactions. 28. Energy is transferred during chemical reactions. D. Completion Fill in the word(s) that will make each statement true. 29. A ________________________ is a form of matter that flows, has a fixed volume, and takes the shape of its container. 30. A ________________________ is a gaseous substance that is generally a liquid or solid at room temperature. 31. A tossed green salad is an example of a ________________________ mixture. 32. The chemical symbol for the element nitrogen is ________________________. 33. In a chemical reaction, the starting substances are called ________________________. 34. The burning of wood is an example of a ________________________ change. 35. The evaporation of water is an example of a ________________________ change. 36. Any matter that has a uniform and definite composition is a(n) ________________________. E. Essay Write a short essay for the following. 37. Name at least one physical property of each of the following four materials that could be used to separate it from a mixture of all four. Describe how you would separate a mixture of salt, water, iron filings, and sawdust. A. Matching Match each description in Column B with the correct term in Column A. Write the letter of the correct description on the line. Column A Column B 1. proton a. the total number of protons and neutrons in the nucleus of an atom 2. atom b. the weighted average mass of the atoms in a naturally occurring sample of an element 3. mass number c. 4. atomic mass unit d. the number of protons in the nucleus of an element 5. electron e. atoms with the same number of protons but different numbers of neutrons 6. isotopes f. negatively charged subatomic particle 7. atomic number g. the smallest particle of an element that retains its identity in a chemical reaction 8. atomic mass h. a horizontal row of the periodic table 9. period i. subatomic particle with no charge 10. neutron j. positively charged subatomic particle 1 the mass of a carbon-12 atom 12 B. Multiple Choice Choose the best answer and write its letter on the line. 11. Which of the following is not a part of Dalton’s atomic theory? a. All elements are composed of atoms. b. Atoms of the same element are alike. c. Atoms are always in motion. d. Atoms that combine do so in simple whole-number ratios. 12. The nucleus of an atom is a. negatively charged and has a low density. b. negatively charged and has a high density. c. positively charged and has a low density. d. positively charged and has a high density. Chapter 4 Atomic Structure 93 Name Date Class 13. Dalton theorized that atoms are indivisible and that all atoms of an element are identical. Scientists now know that a. Dalton’s theories are completely correct. b. atoms of an element can have different numbers of protons. c. atoms are all divisible. d. all atoms of an element are not identical but they all have the same mass. 14. The number of neutrons in the nucleus of an atom can be calculated by a. adding together the numbers of electrons and protons. b. subtracting the number of protons from the number of electrons. c. subtracting the number of protons from the mass number. d. adding the mass number to the number of protons. 15. The sum of the protons and neutrons in an atom equals the a. atomic number. c. atomic mass. b. number of electrons. d. mass number. 16. All atoms of the same element have the same: a. number of protons. b. number of neutrons. c. mass number. d. mass. 17. Which of these statements is false? a. Electrons have a negative charge. b. Electrons have a mass of 1 amu. c. The nucleus of an atom is positively charged. d. The neutron is found in the nucleus of an atom. 18. An atom of an element with atomic number 48 and mass number 120 contains a. 48 protons, 48 electrons, and 72 neutrons. b. 72 protons, 48 electrons, and 48 neutrons. c. 120 protons, 48 electrons, and 72 neutrons. d. 72 protons, 72 electrons, and 48 neutrons. 19. How do the isotopes hydrogen-2 and hydrogen-3 differ? a. Hydrogen-3 has one more electron than hydrogen-2. b. Hydrogen-3 has two neutrons. c. Hydrogen-2 has three protons. d. Hydrogen-2 has no protons. 20. The number 80 in the name bromine-80 represents a. the atomic number. b. the mass number. c. the sum of protons and electrons. d. none of the above 21. Which of these statements is not true? a. Atoms of the same elements can have different masses. b. The nucleus of an atom has a positive charge. c. Atoms of isotopes of an element have different numbers of protons. d. Atoms are mostly empty space. 94 Core Teaching Resources Name Date Class 22. Relative atomic masses are measured in a. nanograms. b. grams. c. angstroms. d. amus. 23. If E is the symbol for an element, which two of the following symbols represent isotopes of the same element? 1. 24 E 12 a. 1 and 2 b. 3 and 4 2. 24 E 13 3. 25 E 11 4. 25 E 12 c. 1 and 4 d. 2 and 3 C. Problems Solve the following problem in the space provided. Show your work. 9 Name Date 25. Complete this table. Atomic Number Mass Number Number of Protons Number of Neutrons 9 Number of Electrons 10 14 7 21 13 20 27 56 26 26. List the number of protons, neutrons, and electrons in each of the following atoms. Protons Neutrons Electrons 13 C 6 10 Be 4 20 Ne 10 11 B 5 13 S 16 A. Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A 1. the ways in which electrons are arranged around the nuclei of atoms 2. the ejection of electrons by metals when light shines on them Column B 3. the region around the nucleus of an atom where an electron is likely to be moving a. Aufbau principle 4. An atomic orbital may describe at most two electrons. 5. the regions within which electrons have the highest probability of being found 6. When electrons occupy orbitals of equal energy, one electron enters each orbital until all the orbitals contain one electron. b. quantum c. photoelectric effect d. atomic orbitals 7. the amount of energy required to move an electron from its present energy level to the next higher one e. Pauli exclusion principle 8. light quanta f. energy level 9. Electrons enter orbitals of lowest energy first. 10. the modern description of the electrons in atoms g. Hund’s rule h. electron configurations i. quantum mechanical model j. photons B. Multiple Choice Choose the best answer and write its letter on the line. 11. Bohr’s contribution to the development of atomic structure a. was referred to as the “plum pudding model.” b. was the discovery that electrons surround a dense nucleus. c. was proposed that electrons travel in circular orbits around the nucleus. d. is the quantum mechanical model. 12. What is the total number of orbitals in the third principal energy level? 120 a. 1 c. 9 b. 4 d. 16 Core Teaching Resources Name Date Class 13. What is the maximum number of electrons allowed in the third energy level? a. 2 c. 18 b. 8 d. 32 14. What is the maximum number of electrons that can occupy one orbital? a.1 c. 8 b.2 d. 18 15. The electron configuration for fluorine is a. 1s22s22p3. c. 1s22s22p6. b. 1s22s22p5. d. 1s22s22p63s2. 16. The first three electrons that enter into p orbitals must have a. parallel spins. c. low energy levels. b. opposite spins. d. opposite charges. 17. The atom whose electron configuration is 1s22s22p63s23p1 is a. B. c. Al. b. Na. d. Ga. 18. The configuration for the outermost energy level in Ca is a. 3s2. c. 2s1. b. 4s2. d. 4s1. 19. The element having the same s and p configurations for principal energy level 3 as the element F has for its principal energy level 2 is a. Na. c. P. b. Al. d. Cl. 20. The frequency and wavelength of all waves are a. directly related. c. unrelated. b. inversely related. d. equal. 21. The SI unit of cycles per second is called a a. photon. c. hertz. b. quantum. d. hund. 22. Among the following groups of atoms, which have the same outer energy level configurations? a. H, He c. Mg, Al, Ca, Ga b. Li, Be, N, Ne d. N, P, As, Bi 23. The wavelength of light with a frequency of 2.50 × 1013 s1 is a. 1.20 × 105 m. c. 1.20 × 105 m. b. 8.33 × 105 m. d. 8.33 × 105 m. 24. Once the electron in a hydrogen atom absorbs a quantum of energy, it a. is now in its ground state. c. has released a photon. b. is now in its excited state. d. none of the above Chapter 5 Electrons in Atoms 121 Name Date C. Problems Solve the following problems in the space provided. Show your work. 25. Write the electron configurations for the following atoms. a. Mg b. P c. Br d. Xe 26. Identify the elements described below. a. Configuration = 1s22s22p63s23p4 b. Contains a full second energy level c. Contains the first d electron d. Contains seven electrons in its fourth energy level e. Contains only two electrons in its fifth energy level f. Contains three unpaired electrons in its third energy level g. Contains five electrons in its 3d orbitals h Has its outermost electron in 7s1 27. What is the frequency of radiation whose wavelength is 6.25 105 cm? 122 Core Teaching Resources Class Name Date Class 28. What is the energy of a photon whose frequency is 5.2 1015 s1? h = 6.6262 1034 Js D. Essay Write a short essay for the following. 29. Distinguish between the Bohr model and the quantum mechanical model of an atom in terms of the positions of the electrons in an atom. E. Additional Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A Column B 30. the lowest energy level within which an electron can be found a. Heisenberg uncertainty principle 31. the height of an electromagnetic wave from the origin to the crest b. wavelength 32. It is impossible to know exactly both the velocity and the position of a particle at the same time. c. ground state 33. the number of electromagnetic wave cycles to pass a given point per unit of time d. amplitude 34. All matter exhibits wavelike motion. 35. the distance between the crests of an electromagnetic wave e. de Broglie’s equation f. frequency Chapter 5 Electrons in Atoms 123 Name Date Class F. True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 36. The energy levels in an atom can be viewed like the rungs on a ladder. 37. The electrons in an atom are arranged in concentric orbits around the nucleus. 38. The principal quantum number equals the number of sublevels within that principal energy level. 39. As many as eight electrons may occupy the same orbital. 40. In all natural phenomena, change proceeds toward the lowest possible energy state. 41. The photoelectric effect will occur only if the frequency of light striking an electron in a metal is above a certain threshold frequency. 42. The behavior of light can be explained in terms of waves. 43. According to the Heisenberg uncertainty principle, as the velocity of a moving particle is known with increasing accuracy, the position of that particle becomes less accurately known. 44. Quantum mechanics describes the motions of subatomic particles and atoms as waves that gain or lose energy in packages called quanta. A. Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A Column B 1. half the distance between the nuclei of two atoms of the same element when the atoms are joined a. electronegativity 2. negatively charged ion b. groups 3. the vertical columns of the periodic table c. atomic radius 4. the nonmetallic elements of Group 7A d. ionization energy 5. elements in which the highest occupied s and p sublevels are filled e. periodic law 6. the tendency for the atoms of an element to attract electrons when the atoms are in a compound f. alkali metals 7. positively charged ion g. halogens 8. the energy required to remove an electron from an atom in the gaseous state h. noble gases 9. the Group 1A elements i. anion 10. When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties. j. cation B. Multiple Choice Choose the best answer and write its letter on the line. 11. The modern periodic table is arranged in order of increasing a. atomic mass. b. atomic number. c. atomic size. d. atomic radius. 12. The elements in Groups 1A through 7A are a. alkali metals. b. alkaline earth metals. c. transition metals. d. representative elements. Chapter 6 The Periodic Table 147 Name Date Class 13. Which of the following is true concerning the noble gases? a. Their highest occupied s and p sublevels are filled. b. They belong to Group 8A. c. They are sometimes referred to as the inert gases. d. all of the above 14. What is the number of electrons in the highest occupied energy level of an element in Group 5A? a.5 c. 8 b.3 d. 18 15. Among the groups of elements listed below, which have the same number of electrons in their highest occupied energy levels? a. Li, B, C, F c. K, Ca, Rb, Sr b. Na, Mg, Al, S d. N, P, As, Sb 16. An element that contains an electron in a d sublevel is a. Mg. c. Fe. b. O. d. Ne. 17. The elements that contain electrons in an f sublevel near the highest occupied energy level are referred to as a. alkali metals. c. transition metals. b. alkaline earth metals. d. inner transition metals. 18. The electron configuration of the element chlorine ends in a. 3s2. c. 3s23p5. 6 b. 3p . d. 3s23p7. 19. The element with 8 electrons in its 3d sublevel is a. O. c. Ar. b. Ne. d. Ni. 20. As you move down a group in the periodic table, atomic size generally a. increases. c. remains the same. b. decreases. d. varies randomly. 21. The largest atom from among the following is a. Li. c. Rb. b. Na. d. Fr. 22. The smallest atom from among the following is a. Na. c. Si. b. Mg. d. Cl. 23. As the number of electrons added to the same principal energy level increases, atomic size generally a. increases. c. remains the same. b. decreases. d. varies randomly. 24. Removing one electron from an atom results in the formation of an 148 a. ion with a 1 charge. c. ion with a 7 charge. b. ion with a 1 charge. d. ion with a 7 charge. Core Teaching Resources Name Date Class 25. Among the elements listed, which would show the largest increase between the second and third ionization energies? a. B c. Ca b. P d. Zn 26. Among the following, which element has the lowest ionization energy? a. Na c. Cs b. Cl d. I 27. Among the following, which element has the highest second ionization energy? a. Na c. Cs b. Cl d. I 28. Which of the following are always larger than the neutral atoms from which they are formed? a. positive ions c. cations b. negative ions d. none of the above 29. The smallest particle from among the following is a. Li. c. F. b. Li. d. F. 30. The least electronegative element from among the following is a. Na. c. Cs. b. Cl. d. S. C. Questions Answer the following in the space provided. 31. Given the outermost energy level configurations below, complete the table by providing the period number, group number, group name (if appropriate), and symbol for each element identified. Element Period No. Group No. Group Name Symbol a. 2s2 b. 3s23p3 c. 3s23p6 d. 4s1 e. 3d14s2 f. 4s24p5 Chapter 6 The Periodic Table 149 Name Date Class 32. Arrange the following elements as described below. Li, C, K, F, Cs a. In order of decreasing atomic size b. In order of increasing ionization energy c. In order of decreasing electronegativity 33. Among the following pairs of atoms, identify the larger of the two, the one with the greater first ionization energy, and the one with the lower electronegativity. Atom Larger Greater Ionization Energy Lower Electronegativity a. Li, K b. C, F c. Mg, Ca d. O, S 34. The outermost energy level configurations for the theoretical elements AE are listed below. Use the symbols A through E to answer each of the questions that follow. A = 3s2 B = 3s1 C = 2s22p6 D = 2s22p5 E = 2s22p3 a. Which has the lowest first ionization energy? ____________________________ b. Which is a noble gas? ____________________________ c. Which has the highest electronegativity? ____________________________ d. Which has the highest second ionization energy? ____________________________ e. Which is the largest atom? ____________________________ D. Essay Write a short essay for the following statement. 35. Explain why elements with high first ionization energies typically also have high electronegativity values. A. Matching Match each description in Column B with the correct term in Column A. Write the letter of the correct description on the line. Column A Column B 1. electron dot structure a. a mixture of two or more elements, at least one of which is a metal 2. ionic compound b. the number of ions of opposite charge surrounding each ion in a crystal 3. valence electron c. the force of attraction binding oppositely charged ions together 4. ionic bond d. the attraction of valence electrons for positive metal ions 5. chemical formula e. a depiction of valence electrons around the symbol of an element 6. halide ion f. compound of cations and anions 7. alloy g. an anion of a halogen 8. octet rule h. an electron in the highest occupied energy level of an atom 9. formula unit i. Atoms in most compounds tend to achieve the electron configuration of a noble gas. 10. coordination number j. shows the kinds and numbers of atoms in the smallest representative unit of a substance 11. metallic bond k. lowest whole-number ratio of ions in an ionic compound B. Multiple Choice Choose the best answer and write its letter on the line. 12. How many valence electrons does an atom of any element in Group 6A have? a. 2 c. 6 b. 4 d. 8 168 Core Teaching Resources Name Date Class 13. The electron dot structure for an atom of phosphorus is a. b. P P c. P d. P 14. When an aluminum atom loses its valence electrons, what is the charge on the resulting ion? a. 2+ c. 3+ b. 2– d. 1+ 15. The electron configuration of a fluoride ion, F–, is a. 1s2 2s2 2p5. b. the same as that of the neon atom. c. 1s2 2s2 2p6 3s1. d. the same as that of a potassium ion. 16. Metals are good conductors of electricity because they a. form crystal lattices. b. contain positive ions. c. contain mobile valence electrons. d. form ionic bonds. 17. In forming chemical bonds, atoms tend to attain an element is the a. a state of higher energy. b. the electron configuration of noble gas atoms. c. the electron configuration of halogen atoms. d. all of the above 18. An ionic compound is a. electrically neutral. b. held together by ionic bonds. c. composed of anions and cations. d. all of the above 19. Which of these is not a characteristic of most ionic compounds? a. solid at room temperature b. has a low melting point c. conducts an electric current when melted d. produced by reaction between metallic and nonmetallic elements 20. A metallic bond is a bond between a. valence electrons and positively charged metal ions. b. the ions of two different metals. c. a metal and nonmetal. d. none of the above 21. Which element when combined with chlorine would most likely form an ionic compound? a. lithium c. phosphorus b. carbon d. bromine 22. A cation is any atom or group of atoms with a. a positive charge. b. no charge. c. a negative charge. d. more electrons than the corresponding atoms. Chapter 7 Ionic and Metallic Bonding 169 Name Date Class 23. The cation Fe3+ is formed when a. an atom of iron loses two electrons. b. an atom of zinc loses two electrons. c. an atom of iron loses three electrons. d. an atom of iron gains three electrons. C. True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. 24. The chemical properties of an element are largely determined by the number of valence electrons the element has. 25. Fluorine and chlorine each have one valence electron. 26. The coordination number gives the total number of ions in a crystal. 27. Atoms acquire the stable electron structure of a noble gas by losing electrons. 28. An alloy is a mixture of two or more elements, of which at least one is a metal. 29. The crystal structure of ionic compounds such as sodium chloride is very unstable. 30. When melted, ionic compounds conduct electricity. 31. Metals are ductile because the cations in a piece of pure metal are insulated from one another by a sea of electrons. 32. Metal atoms are arranged in a face-centered cubic structure. 33. During the formation of ionic compounds, electrons are transferred from one atom to another. D. Questions Answer the following in the space provided. 34. Write electron dot structures for the atoms and ions of each of the following elements. Atoms Ions a. Ca b. Br c. Al A. Matching Match each term in Column B with the correct description in Column A. Write the letter of the correct term on the line. Column A 1. the mixing of several atomic orbitals to form the same number of equivalent hybrid orbitals 2. two or more valid electron dot formulas that can be written for the same molecule 3. a chemical formula that shows the arrangement of atoms in molecules and polyatomic ions 4. the weakest attractions that exist between molecules 5. Because electron pairs repel, molecules adjust their shapes so that the valenceelectron pairs are as far apart as possible. Column B 6. a covalent bond in which one pair of electrons is shared between two atoms 7. a molecule in which one end is slightly negative and the other end is slightly positive 8. a covalent bond formed between two different atoms in which the bonding electrons are shared unequally 9. an electrically neutral group of atoms joined together by covalent bonds 10. a covalent bond in which one atom contributes both bonding electrons a. molecular compound b. VSEPR theory c. van der Waals forces d. single covalent bond e. resonance structures f. polar molecule g. hybridization h. structural formula i. polar covalent bond j. coordinate covalent bond Chapter 8 Covalent Bonding 201 Name Date Class B. Multiple Choice Choose the best answer and write its letter on the line. 11. Which of the following exists as a diatomic molecule? a. He c. Cl b. Ar d. Na 12. The diatomic molecule among the following that contains a single covalent bond is a. F2. c. N2. b. O2. d. O2. 13. Atoms share electrons in order to acquire the electron configurations of a. alkali metals. c. halogens. b. alkaline earth metals. d. noble gases. 14. In Cl2, what is the total number of unshared pairs of electrons? a. 1 c. 4 b. 2 d. 6 15. The diatomic molecule among the following that contains a triple covalent bond is a. O2. c. H2. b. Cl2. d. N2. 16. In the N2 molecule, what is the number of unshared pairs of electrons in each nitrogen atom? a. 1 c. 3 b. 2 d. 4 17. The covalent molecule among the following is a. NaCl. c. CaO. b. NH3. d. KF. 18. How many single covalent bonds are there in a molecule of CH4? a. 1 c. 3 b. 2 d. 4 19. How many double covalent bonds are there in a molecule of CO2? a. 1 c. 3 b. 2 d. 4 20. The molecule among the following that contains only one single covalent bond is a. NH3. c. HI. b. N2. d. H2O. 21. In forming the molecule HF, the F atom attains the electron configuration of 202 a. He. c. Ar. b. Ne. d. Cl. Core Teaching Resources Name Date Class 22. Which molecule among the following contains a coordinate covalent bond? a. CO c. H2O b. NH3 d. CCl4 23. The molecule among the following that exhibits resonance structures is a. CO2. c. O3 (ozone). b. CH4. d. NH3. 24. Resonance structures can be considered a. polar molecules. c. coordinate covalent molecules. b. hybrids. d. none of the above 25. Substances that show relatively strong attractions to an external magnetic field are said to be a. diamagnetic. c. nonmagnetic. b. paramagnetic. d. none of the above 26. Oxygen is an example of a substance that is a. diamagnetic. c. nonmagnetic. b. paramagnetic. d. none of the above 27. When two atomic orbitals combine to form a molecular orbital that is symmetrical along the axis connecting the two atomic nuclei, the bond that is produced is referred to as a(n) a. ionic bond. c. sigma bond. b. pi bond. d. none of the above 28. The shape of a molecule of NH3 is said to be a. tetrahedral. c. bent. b. pyramidal. d. linear. 29. In a methane (CH4) molecule, the mixing of one 2s orbital with three 2p orbitals forms a. one sp4 hybrid orbital. c. one sp3 hybrid orbital. b. four sp hybrid orbitals. d. four sp3 hybrid orbitals. 30. The overlap of atomic s orbitals produces a (n) a. ionic bond. c. sigma bond. b. pi bond. d. none of the above 31. Which of the following contains a polar covalent bond? a. O2 c. CaO b. MgCl2 d. HF 32. What type of bond would be expected in a molecule of LiF? a. ionic bond c. nonpolar covalent bond b. polar covalent bond d. none of the above Chapter 8 Covalent Bonding 203 Name Date Class 33. Among the following molecules, the one containing the most polar bond is a. HF. c. HBr. b. HCl. d. H2O. 34. The polar molecule among the following is a. CCl4. c. H2O. b. CO2. d. N2. 35. The strongest intermolecular attractive forces from among those listed are a. dispersion forces. c. hydrogen bonds. b. dipole interactions. d. cannot be determined 36. The melting and boiling points of most molecular compounds are a. lower than those of most ionic compounds. b. about the same as those of most ionic compounds. c. higher than those of most ionic compounds. d. sometimes higher and sometimes lower than those of most ionic compounds. 37. Network solids a. have low melting points. c. are extremely hard. b. have low boiling points. d. are generally ductile.