Chemistry Section Name: MID TERM STUDY GUIDE Date: A. Multiple Choice. 1. The mass of a proton is approximately equal to the mass of (1) an alpha particle (2) a beta particle (3) a positron (4) a neutron 2. An orbital of an atom is defined as the most probable location of (1) an electron (2) a neutron (3) a positron (4) a proton 3. At STP, which physical property of aluminum always remains the same from sample to sample? (1) mass (2) density (3) length (4) volume 4. What must occur when an electron in an atom returns from a higher energy state to a lower energy state? (1) A specific amount of energy is released. (3) The atom undergoes transmutation. (2) A random amount of energy is released. (4) The atom spontaneously decays. 5. Which phrase describes the distribution of charge and polarity of a CH 4 molecule? (1) symmetrical and polar (3) asymmetrical and polar (2) symmetrical and nonpolar (4) asymmetrical and nonpolar 6. Which list of elements consists of a metal, a metalloid, and a nonmetal? (1) Li, Na, Rb (2) Cr, Mo, W (3) Sn, Si, C (4) O, S, Te 7. Which diagram represents a mixture of two different molecular forms of the same element? 8. Which substance can be decomposed by a chemical change? (1) beryllium (2) boron (3) methanol (4) magnesium Created 17 January 2017
9. Which Lewis electron-dot diagram represents a nitrogen atom in the ground state? 10. What is the most likely electronegativity value for a metallic element? (1) 1.3 (2) 2.7 (3) 3.4 (4) 4.0 11. Which polyatomic ion has a charge of 3? (1) chromate ion (2) oxalate ion (3) phosphate ion (4) thiocyanate ion 12. Which equation represents natural transmutation? 10 4 13 1 (1) 5 B + 2He 7 N + 0 n (3) S + 2e S 2 14 14 (2) 6 C 7 N + 1 0 e (4) Na Na + + e 13. Given the equation representing a nuclear reaction in which X represents a nuclide: 232 4 90Th 2He + X Which nuclide is represented by X? 236 228 236 228 (1) 92Ra (2) 88Ra (3) 92U (4) 88U 14. Every chlorine atom has (1) 7 electrons (3) a mass of 35 (2) 17 neutrons (4) an atomic number of 17 15. The diagram below represents the bright line spectra of four elements and a bright line spectrum produced by a mixture of three of these elements. Which element is not present in the mixture? (1) Element A (2) Element D (3) Element X (4) Element Z
16. Compared to the mass and the penetrating power of an alpha particle, a beta particle has (1) less mass and greater penetrating power (3) more mass and greater penetrating power (2) less mass and less penetrating power (4) more mass and less penetrating power 17. An atom in the ground state has two electrons in its first shell and six in its second shell. What is the total number of protons in the nucleus of this atom? (1) 5 (2) 2 (3) 7 (4) 8 18. A bromine atom in an excited state could have an electron configuration of (1) 2 8 18 6 (2) 2 8 18 7 (3) 2 8 17 7 (4) 2 8 17 8 19. The atomic masses and the natural abundances of the two naturally occurring isotopes of lithium are shown in the table below Which numerical setup can be used to determine the atomic mass of lithium? (1) (0.075)(6.02 u) + (0.925)(7.02 u) (3) (7.5)(6.02 u) + (92.5)(7.02 u) (2) (0.925)(6.02 u) + (0.075)(7.02 u) (4) (92.5)(6.02 u) + (7.5)(7.02 u) 20. A solid element that is malleable, a good conductor of electricity, and reacts with oxygen is classified as a (1) metal (2) metalloid (3) noble gas (4) nonmetal 21. What is the oxidation number of iodine in KIO 4? (1) +1 (2) 1 (3) +7 (4) 7 22. Which compound has the smallest percent composition by mass of chlorine? (1) HCl (3) LiCl (2) KCl (4) NaCl 23. In the compound KHSO 4, there is an ionic bond between the (1) KH + 2 and the SO 4 ions (3) K + and the HS ions + (2) KHSO 3 and the O 2 ions (4) K + 2 and the HSO 4 ions
Base your answers to questions 24 and 25 on the information below. Information about Two Mixtures at 20. C Group 1 Group 17 Particle Radius (pm) Particle Radius (pm) Li atom Li + ion Na atom Na + ion K atom K + ion Rb atom Rb + ion 130. 78 160. 98 200. 133 215 148 F atom F ion Cl atom Cl ion Br atom Br ion I atom I ion 60. 133 100. 181 117? 136 220. 24. The radius of a bromine ion is approximately (1) 117 pm (2) 181 pm (3) 195 pm (4) 221 pm 25. The name and the charge of the particle gained by a fluorine atom when the fluorine atom becomes an ion are (1) neutron, 0 (2) positron, +1 (3) proton, +1 (4) electron, 1 26. What is the name of the sodium salt of phosphoric acid? (1) sodium hypophosphite (3) sodium phosphide (2) sodium phosphate (4) sodium phosphite 27. Which formula is also an empirical formula? (1) CH 4 (2) H 2 O 2 (3) C 4 H 10 O 2 (4) C 3 H 6 O 3 28. What is the name of the compound with the formula N 2 O 5? (1) nitrogen (V) oxide (3) nitrogen (III) oxide (2) nitrogen (II) oxide (4) nitrogen (IV) oxide 29. What is the total number of atoms represented by the formula BaCl 2 2H 2 O? (1) 5 (2) 8 (3) 9 (4) 18 30. Which is the correct formula for iron (II) oxide? (1) FeO 2 (2) FeO (3) Fe 2 O 3 (4) Fe 3 O 4 31. Which element is brittle in the solid phase and is a poor conductor of heat and electricity? (1) calcium (2) strontium (3) sulfur (4) copper
32. Polar covalent bonds are caused by (1) unbalanced ionic charges (3) the transfer of electrons between atoms (2) unequal electronegativity values (4) equally shared valence electrons 33. Which compound has the strongest hydrogen bonding between its molecules? (1) HBr (2) HCl (3) HF (4) HI 34. Which kind of energy is stored in a chemical bond? (1) potential energy (3) activation energy (2) kinetic energy (4) ionization energy 35. Which type of solid does pure water form when it freezes? (1) ionic (2) network (3) metallic (4) molecular
B. Short Answer. Base your answers to questions 36 through 38 on the information below and on your knowledge of chemistry. The balanced equation below represent a reaction. O 2 (g) + energy O (g) + O (g) 36. Identify the type of chemical bond in a molecule of the reactant. double bond or nonpolar covalent bond 37. In the space to the right, draw a Lewis electron-dot diagram of one oxygen atom. 38. Explain, in terms of bonds, why energy is absorbed during this reaction: Bond breaking always requires energy
Base your answers to questions 39 through 42 on the information below and on your knowledge of chemistry. Before atomic numbers were known, Mendeleev developed a classification system for the 63 elements known in 1872 using oxide formulas and atomic masses. He used an R in the oxide formulas to represent any element in each group. The atomic mass was listed in parentheses after the symbol of each element. A modified version of Mendeleev s classification system is shown in the table below. 39. Identify one characteristic used by Mendeleev to develop his classification system of the elements. Oxide formulas. or Atomic masses. 40. Based on Mendeleev s oxide formula, what is the number of electrons lost by each atom of the elements in Group III? Three electrons are lost by each atom. 41. Based on Table J, identify the least active metal listed in Group I on Mendeleev s table. According to Table J, silver (Ag) is the least active metal in Group I. 42. Explain, in terms of chemical reactivity, why the elements in Group 18 on the modern Periodic Table were not identified by Mendeleev at that time. Mendeleev based his table on oxide formulas and Group 18 elements do not form oxides.
Base your answers to questions 43 through 45 on the information below and on your knowledge of chemistry. The ionic radii of some Group 2 elements are given in the table below. Ionic Radii of Some Group 2 Elements Atomic Ionic Symbol Number Radius (pm) Be 4 44 Mg 12 66 Ca 20 99 Ba 56 134 43. On the grid above, mark an appropriate scale on the axis labeled Ionic Radius (pm). 44. On the grid above, plot the data in the Ionic Radii table. 45. Strontium (Sr) is also in Group 2. Estimate the radius of strontium on the graph above. Sr 116 pm