| Questions | Answer | Explanations |
31 Which radioisotope undergoes beta decay and has a half-life of less than 1 minute?(1) Fr-220 (3) N-16 (2) K-42 (4) P-32 | 3 | nuclear section- Use table N to determine the decay mode |
32 Which set of symbols represents atoms with valence electrons in the same electron shell?(1) Ba, Br, Bi (3) O, S, Te (2) Sr, Sn, I (4) Mn, Hg, Cu | 2 | All the elements are in the same period |
33 When compared with the energy of an electron in the first shell of a carbon atom, the energy of an electron in the second shell of a carbon atom is(1) less (2) greater (3) the same | 2 | more energy in the higher energy levels |
34 What is the total number of electrons found in an atom of sulfur?(1) 6 (2) 8 (3) 16 (4) 32 | 3 | 2-8-6 atoms are neutral (from Switzerland) |
35 Which electron configuration represents the electrons of an atom in an excited state?(1) 2–8–1 (3) 2–8–17–6 (2) 2–8–6 (4) 2–8–18–5 | 3 | Count the electrons and check that element for the same configuration note an electron has been promoted in #3 |
36 The nucleus of an atom of cobalt-58 contains (1) 27 protons and 31 neutrons (2) 27 protons and 32 neutrons (3) 59 protons and 60 neutrons (4) 60 protons and 60 neutrons | 1 | cobalt has an atomic number of 27=protons 58 - 27- 31 neutrons |
37 Which pair of formulas correctly represents a molecular formula and its corresponding empirical formula?(1) C 2H2 and CH (3) C4H6 and CH(2) C 3H4 and CH2 (4) C5H8 and C2H2 | 1 | empirical formulas are the lowest ratio of atoms in a formula |
38 Which substance is correctly paired with its type of bonding?(1) NaBr—nonpolar covalent (2) HCl—nonpolar covalent (3) NH 3—polar covalent(4) Br 2—polar covalent | 3 | bonding- look at the electronegativity differences between the elements |
39 A gas occupies a volume of 444 mL at 273 K and 79.0 kPa. What is the final kelvin temperature when the volume of the gas is changed to 1880 mL and the pressure is changed to 38.7 kPa?(1) 31.5 K (3) 566 K (2) 292 K (4) 2360 K | 3 | PV/T = PV/T |
40 At STP, which of these substances is most soluble in H2O?(1) CCl 4 (3) HCl(2) CO 2 (4) N2 | 3 | The polar substance dissolves in water like dissolves like water is polar and so is HCl |