chem 100 exam 2 questions and correct detailed answers

The strongest interactions between molecules of ammonia ( NH3) are A) dipole-dipole. B) dispersion forces. C) hydrogen bonds. D) ionic bonds. E) polar covalent. - correct answers C) hydrogen bonds. Significant figures are important because they indicate A) the number of measurements. B) the accuracy of a measurement. C) the accuracy of the conversion factor. D) the precision of a measurement. E) the number of digits on a calculator. - correct answers D) the precision of a measurement. The name of the Cu+ ion is A) copper(II). B) cuprum. C) cobalt D) copper. E) copper(I). - correct answers E) copper(I). Which of the following types of radiation has the highest energy? A) beta-particles B) alpha-particles C) gamma-rays D) visible light E) All of these have the same energy. - correct answers C) gamma-rays In ionic compounds, ________ lose their valence electrons to form positively charged ________. A) nonmetals; cations B) metals; polyatomic ions C) nonmetals; anions D) metals; anions E) metals; cations - correct answers E) metals; cations The number of electron levels in a magnesium atom is A) 1. B) 2. C) 3. D) 4. E) 5 - correct answers C) 3. The shape of the carbon tetrachloride molecule is A) pyramidal. B) tetrahedral. C) linear. D) octagonal. E) square. - correct answers B) tetrahedral. In a molecule with covalent bonding A) atoms are held together by sharing electrons. B) oppositely charged ions are held together by strong electrical attractions. C) atoms of metals form bonds to atoms of nonmetals. D) atoms of noble gases are held together by attractions between oppositely charged ions. E) atoms of different metals form bonds. - correct answers A) atoms are held together by sharing electrons. What is missing in the nuclear reaction shown below? 10 5 B + 4 2 He ________ + 1 0 n A) a neutron B) 13 5 N C) 13 7 B D) 13 7 N E) 14 7 N - correct answers D) 13 7 N What is required for a nuclear transmutation to occur? A) very high temperature B) a corrosive environment C) gamma emission D) a particle to collide with a nucleus E) spontaneous nuclear decay - correct answers D) a particle to collide with a nucleus There are more students skipping an afternoon class because afternoon naps are important. Considering the concepts of the Scientific Method this would be a(n) A) hypothesis. B) theory. C) experiment. D) observation. E) all the above - correct answers A) hypothesis. Which of the following is not a base SI unit? A) meters B) seconds C) inches D) kilograms E) mo - correct answers C) inches At this time, elements with an atomic number greater than __________ have not been found in nature. A) 266 B) 78 C) 87 D) 92 E) 275 - correct answers D) 92 The VSEPR theory allows us to determine the most favorable A) color of a compound. B) charge on an ion. C) formula for a compound. D) shape of a molecule. E) bond type for a molecule. - correct answers D) shape of a molecule. A sample of cerium -141 for a diagnostic test was dissolved in saline solution to an activity of 4.5 mCi/mL. If the patient undergoing the test needs a dose of 10. mCi, how much of the solution should be injected into the patient? A) .45 mL B) 45 mL C) 22 mL D) 2.2 mL E) 4.5 mL - correct answers D) 2.2 mL Which one of the following, by definition, cannot be a pure substance? A) sugar crystals B) pure water droplets C) carbon powder D) solid gold E) kool aid - correct answers E) kool aid What is the formula of the nitride ion? A) NO3 3- B) N3- C) NO2 - D) NO3 - E) NO3 2 - correct answers B) N3- The electron dot symbol below could represent which of the following elements? A) Al B) O C) Ne D) Na E) C - correct answers B) O When an alpha particle is emitted from the nucleus of an atom, the nuclear mass A) decreases by two units. B) increases by one unit. C) decreases by four units. D) increases by two units. E) remains the same. - correct answers C) decreases by four units. In an electron-dot structure of an element, the dots are used to represent A) only the electrons that will participate in bond formation. B) the electrons that the element will gain when it forms a compound. C) all of the electrons in the atom. D) the valence electrons. E) the electron arrangement. - correct answers D) the valence electrons. An anion always A) has a positive charge. B) has a negative charge. C) contains a metal and a nonmetal. D) forms covalent bonds. E) contains a group of two or more atoms with a positive charge. - correct answers B) has a negative charge. What is the abbreviated electron configuration for nickel (atomic number 28)? A) [Ar]4s 24p 4 B) [Kr]4s 23d 8 C) [Ar]3d 8 D) [He]2s 22p 3 E) [Ar]4s 23d 8 - correct answers E) [Ar]4s 23d 8 The octet rule indicates that A) all of the shells in an atom hold a maximum of 8 electrons. B) the noble gases react with other compounds to get 8 valence electrons. C) all of the noble gases have eight total electrons. D) atoms lose, gain, or share valence electrons to have 8 valence electrons. E) all of the Group A elements have 8 valence electrons. - correct answers D) atoms lose, gain, or share valence electrons to have 8 valence electrons Which of the following elements has the lowest electronegativity? A) O B) Li C) N D) C E) F - correct answers B) Li The p sublevel can hold a total of how many electrons? A) 2 B) 6 C) 10 D) 3 E) 4 - correct answers B) 6 How many valence electrons are in the electron-dot structure of H2O? A) 6 B) 4 C) 8 D) 2 E) 10 - correct answers C) 8 According to the Bohr atomic model, the third energy level in an atom can hold how many electrons? A) 9 B) 6 C) 18 D) 2 E) 8 - correct answers C) 18 Which one of the following is most likely to lose electrons when forming an ion? A) S B) F