PHSC 1: Ch.15

25 July 2022
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1) Why is it so easy for a magnesium atom to lose two electrons?
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B) These two electrons are well shielded from the nuclear charge.
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2) If you mix a typical iodine ion (I, atomic no. = 53) with a typical barium ion (Ba, atomic no. = 56), what compound is formed?
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E) BaI 2
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3) MgCl crystals are composed of 2
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E) a multitude of Mg^2+ ions and Cl- ions grouped together in a three-dimensional array with a 1:2 ratio of Mg^2+ to Cl-.
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4) Which of the following would be an ion with a double positive charge?
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D) an Mg atom that loses two electrons
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5) Which of the above substances would have the lowest boiling point?
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A) a (O=C=O)
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6) How many covalent bonds would the following atom usually form?
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C) 3 . .. X . .
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7) Why are ores so valuable?
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B) Metals can be efficiently extracted from them.
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8) The charges with sodium chloride are all balanced-for every positive sodium ion there is a corresponding negative chloride ion. Since its charges are balanced, how can sodium chloride be attracted to water, and vice versa?
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B) As a water molecule gets close to the sodium chloride it can distinguish the various ions and it is thus attracted to an individual ion by ion-dipole forces.
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9) If carbonic acid (H2CO3) were to undergo ionization, what would one of the products be?
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C) CO -2 3
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10) The separation of charges within a polar molecule is called a(n)
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D) dipole.
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11) How many nonbonding pairs of electrons are in the following molecule? H-H
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C) 0 pairs
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12) Why is it better to recycle metals than to mine more?
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B) It takes far less energy to recycle.
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13) What is the compound that forms if you react potassium and sulfur?
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B) K S 2
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14) Does an ionic bond have a dipole?
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D) Yes, the ionic bond is an example of a very strong dipole.
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15) Which of the following molecules is most likely to show a dipole-dipole interaction?
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B) H S 2
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16) What is a molecule?
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A) a group of atoms that are held together by covalent bonds
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17) The boiling point of 1,4-butanediol is 230°C. Would you expect this compound to be soluble or insoluble in room-temperature water?
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D) Water would be attracted to both ends of 1,4 butanediol, and it is infinitely soluble in water.
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18) Given that the total number of atoms on our planet remains fairly constant, how is it ever possible to deplete a natural resource such as a metal?
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B) The problem is with the expense of collecting metal atoms that are uniformly dispersed.
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19) Atoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why?
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A) They have a great tendency to lose electrons.
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20) What property of alloys make them ideal for developing new materials?
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C) The characteristics of the material change depending on how much of each component is present.
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21) Which of the following is a negative ion?
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D) O^-2
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22) Which of the following best describes ionic bonding?
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B) one atom giving up some of its electrons to another atom
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23) Atoms of nonmetallic elements form covalent bonds, but they can also form ionic bonds. How is this possible?
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C) An ionic bond results when a nonmetallic elements gains an electron from a metallic element.
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24) What needs to be done to convert a neutral nitrogen atom into an N^-3 species?
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C) add three electrons
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25) Why is calcium fluoride, CaF2, a high melting point crystalline solid while stannic chloride, SnCl4, is a volatile liquid?
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D) Ionic compounds formed by elements on opposite sides of the periodic table, like CaF 2, tend to have higher melting points than more covalently bonded structures, like SnCl 4.
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26) An individual carbon-oxygen bond is polar. Yet carbon dioxide, CO2, which has two carbon-oxygen bonds, is nonpolar because
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D) Two of the above are reasonable. ( the molecule has an even number of electrons,the electron-pulls of the two oxygen atoms are equal and opposite,it has a greater symmetry.)
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27) Which of the above substances would have the largest dipole?
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C) c .. H-O-H ..
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28) What molecule loses a proton to form the hydroxide ion, OH⁻?
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C) the water molecule, H O 2
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29) How many more electrons can fit within the valence shell of a hydrogen atom?
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D) 1
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30) If a neutral atom gains two electrons, what is the electrical charge of the atom?
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C) -2
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31) Dipole-induced dipole forces of attraction exist between water and gasoline, and yet these two substances do not mix because water has such a strong attraction for itself. Which of the following compounds might best help to make these two substances mix into a single liquid phase?
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A) the molecule on the far left because the O-H bond is polar and the carbon and hydrogen bonds are nonpolar
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32) Which of the following elements will most likely form an ion with a -2 charge?
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D) S
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33) If an ionic bond is stronger than a dipole-dipole interaction, how can water dissolve an ionic compound?
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B) The ion-dipole interactions of a bunch of water molecules gang up on the strong ionic bond and pull it into the solution.
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34) Which of the following molecules is most likely to show a dipole-dipole interaction?
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E) A and B (CH3OH,)CH3SH)
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35) A substance consisting of which molecule shown below should have a higher boiling point?
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B) The molecule on the right, C2H2Cl, because of electronegativity considerations.
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36) How many oxide ions (O^-2) are needed to balance the positive charge of a titanium ion (Ti^+4)?
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C) 2
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37) Metals are often used for making designer jewelry because they
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E) C and D (are shiny,are strong but can be bent.)
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38) What does the line in the following example actually represent? HH
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E) A and B (a shared pair of electrons,a covalent bond)
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39) If the following generic atom were to undergo ionization, what would be the charge of the most likely product? .X.
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D) +2
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40) Which of the following bonds would be the most polar?
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D) C-F
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41) Which of the following elements has two valence electrons?
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D) Mg
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42) The concept of a chemical bond is
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B) how two or more atoms are held together.
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43) Which of the following is the correct electron dot structure for chlorine (atomic no. = 17)?
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D) d .. .. Cl . ..
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44) The neon atom tends not to lose any electrons because
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C) of its relatively strong effective nuclear charge.
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45) An atom loses an electron to another atom. Is this an example of a physical or chemical change?
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D) chemical change involving the formation of ions
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46) Which of the following elements has six valence electrons?
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D) O
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47) Which molecule is most polar?
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A) O=C=S
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48) How is it possible for a neutral molecule, such as water, to form an ion?
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A) It can combine with a hydrogen ion to form a positively charged species.
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49) Many of the macroscopic properties of a compound depend on
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C) how the atoms of the molecules are held together.
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50) If the following generic atom were to undergo ionization, what would be the charge of most likely product? . .. X . .
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C) -3
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51) Which of the following elements will most likely form an ion with a +2 charge?
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B) Mg
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52) How are oxygen molecules attracted to water molecules?
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C) As a water molecule is brought close to an oxygen molecule an induced dipole results in the O2 molecule causing the attraction.
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53) List the following bonds in order of increasing polarity
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C) N-N < N-O < N-F < H-F
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54) There is more gold in 1 km^3 of the ocean than the amount of gold mined in all of recorded history. How come we do not mine the oceans?
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D) all of the above ( It would take too much energy,It would cost too much,It is too dilute to separate.)
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55) Why are the melting temperatures of most ionic compounds far greater than the melting temperatures of most covalent compounds?
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D) Ionic bonds are so much stronger than the molecular attractions between covalently bonded compounds.
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56) Distinguish between a metal and a metal-containing compound.
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A) Only one of these contains ionic bonds.
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57) What is happening at the molecular level when a polar molecule like water interacts with a typical sodium ion?
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B) The water molecule aligns such that the oxygen interacts with the sodium.
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58) If you mix a typical aluminum ion (Al, atomic no. = 13) with a typical oxygen ion (O, atomic no. = 8), what compound is formed?
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C) Al2O3
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59) If the concentration of gold in seawater is 2.0 milligram per ton of sea water and the mass of the ocean is 1.5 × 10^18 tons, how much gold is in the ocean?
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D) 3.0 × 10^12 kg
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60) Which of the following substances contains F- ions?
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B) CaF 2
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61) Chlorine, Cl2, is a gas at room temperature, but bromine, Br2, is a liquid. Explain.
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B) Bromine atoms are larger and this makes the formation of induced dipole-induced dipole attractions more favorable.
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62) Which of the following would have the highest boiling point?
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B) I 2
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63) Which of the following would have the highest boiling point?
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C) C12H26
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64) Which of the following substances is pure?
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D) all of the above (an ionic compound consisting of sodium and chlorine ions,an element,a covalent compound consisting of one type of molecule)
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65) Which of the following molecules is polar?
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C) c
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66) Which of the following is the weakest?
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B) an induced dipole-induced dipole attraction
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67) How do the electron-dot structures of elements in the same group in the periodic table compare with one another?
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B) Elements of the same group have the same number of valence electrons
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68) Which of the following is not a property of metal?
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A) does not conduct heat well
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69) The source of an atomʹs electronegativity is the
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C) positively charged atomic nucleus.
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70) Magnesium ions carry a 2+ charge, and chloride ions carry a 1- charge. What is the chemical formula for the ionic compound magnesium chloride?
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C) MgCl2
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71) Which of the following is the correct electron dot structure for carbon (atomic no. = 6)?
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E) e . . C . .
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72) Which of the following statements describes a polar molecule?
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E) None of these statements describe polar molecules. (Polar molecules have the weakest intermolecular interactions with ionic compounds,The electrons in the molecule are distributed evenly throughout the molecule,The molecules are usually not attracted to one another very strongly,The molecules have a high degree of symmetry.)
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73) Which of the following intermolecular forces best describes why molecules like sucrose (which has many OH groups) are very water soluble?
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D) hydrogen bonding
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74) Which is more polar, a sulfur-bromine (S-Br) bond or a selenium-chlorine (Se-Cl) bond?
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C) A selenium-chlorine bond should be more polar because of a greater difference in effective nuclear charge.
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75) Which of the following molecules is most likely to show the strongest hydrogen bonding?
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D) CH3OH
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76) What is the main difference between a dipole-dipole interaction and a dipole-induced dipole interaction?
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A) Both are similar, but one involves a temporary dipole created by a permanent dipole.
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77) Which of the following is an ion?
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E) none of the above (no HCl ,2 H2,Au + 3 Br2,Br2)
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78) How many valence electrons does bromine (Br, atomic no. = 35) have?
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A) 7
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79) How many valence electrons does gallium (Ga, atomic no. = 31) have?
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E) 3
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80) Ammonia, NH3, is more polar than is borane, BH3 because it
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D) all of the above (its hydrogens are not exactly opposite one another,has a lone pair of electrons,is less symmetrical than borane.)
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81) Water, H2O, and methane, CH4, have about the same mass and differ by only one type of atom.
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D) all of the above (The water molecule is less symmetrical than is the methane molecule,The electronegativity difference between oxygen and hydrogen is greater than the electronegativity difference between carbon and hydrogen,The oxygen of a water molecule has two lone pairs of electrons.)
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82) Why does an atom with many valence electrons tend to gain electrons rather than lose any?
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B) Atoms with many valence electrons tend to have relatively strong forces of attraction between the valence electrons and the nucleus. This makes it easy for them to gain additional electrons.
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83) Which of the following is not an ion?
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E) O2
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84) Which of the following molecules has the highest boiling point?
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C) NH3
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85) Given the following diagram, describe what happens electronically between these two molecules.
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C) Oxygen B becomes slightly positively charged due to the electrons on the water molecule.
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86) Why doesnʹt the sodium atom gain seven electrons so that its third shell becomes the filled outermost shell?
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C) Sodiumʹs nuclear charge is not strong enough to hold that many more electrons.
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87) Which of the following elements will most likely not form an ion at all?
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D) Ar
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88) If a neutral atom loses one electron, what is the electrical charge of the atom?
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B) +1
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89) Which of the following elements will most likely form an ion with a -1 charge?
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B) Cl
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90) Which would you expect to have a higher melting point: sodium chloride, NaCl, or cesium chloride, CsCl? Why?
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A) The sodium chloride has a higher melting point because its ions are smaller, which allows oppositely charged ions to get closer.
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91) Given the following diagram, describe what happens electronically between these two molecules.
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D) Oxygen A becomes slightly positively charged due to the protons on the water molecule.
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92) Consider the boiling points of the following compounds and their solubilities in room-temperature water. Why does the solubilities in water go down as the boiling points of these alcohols go up.
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B) Larger molecules are more attracted to one another by induced dipole-induced dipole as well as by dipole-dipole and dipole-induced dipole attractions.
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93) Which of the following describes an aqueous solution?
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D) a mixture of some compound dissolved in water
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94) What is the valence shell?
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B) It is the outermost shell of electrons in an atom.
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95) What property of metal atoms account for many of the observed bulk phenomena seen in metal samples?
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B) Metal atoms easily lose one or more outer electrons.
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96) Which of the following would have the lowest melting point?
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D) CF4
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97) Which of the following elements will most likely form an ion with a +1 charge?
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A) Na
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98) Which would you expect to have a higher melting point: sodium chloride, NaCl, or aluminum oxide, Al2O3?
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C) The aluminum oxide has a higher melting point because of the greater charges of the ions, and hence the greater force of attractions between them.
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99) Which of the following has the greatest number of nonbonding pairs of electrons?
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A) F
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100) Which bond is most polar?
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A) O-H
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101) In which of the following molecules will water induce a temporary dipole?
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D) all of the above (N2,O2,CO2)
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102) The neon atom tends not to gain any additional electrons because
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B) there is no more room available in its outermost occupied shell.
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103) How is the number of unpaired valence electrons in an atom related to the number of bonds that the atom can form?
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A) The number of unpaired valence electrons in an atom is the same as the number of bonds that the atom can form.
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104) What is a hydrogen bond?
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C) a special type of dipole-dipole attraction involving hydrogen bound to a highly electronegative atom
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105) List the following compounds in order of increasing boiling point: CI4, CBr4,CCl4, CF4.
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A) CF4, CCl4, CBr4, CI4
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106) Is an ionic compound an example of a chemical compound, or is a chemical compound an example of an ionic compound?
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B) An ionic compound is an example of a chemical compound.
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107) What is the name for the following polyatomic ion? CH3CO2^-1
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E) acetate
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108) Which of the following intermolecular forces best describes why molecules like CF3CF3 are soluble in liquid CO2?
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E) induced dipole-induced dipole
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109) Barium ions carry a 2+ charge, and nitrogen ions carry a 3- charge. What would be the chemical formula for the ionic compound barium nitride?
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A) Ba3N2
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110) How many covalent bonds would the following generic atom usually form? .. .. X .. ..
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E) would usually not form any covalent bonds
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111) Which of the following statements best describes a relatively polar bond?
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D) a very electronegative atom and a weakly electronegative atom are covalently bound
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112) Which of the following molecules should have the same molecular shape and approximate bond angles as ammonia, NH3?
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B) PH3
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113) Which of the following molecules contains an ionic bond?
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D) MgCl2
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114) Take money away from your bank account and the bank will show a negative credit. Take an electron away from an atom, however, and the atom shows up positive. Explain.
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A) Neutral atoms contain identically charged but oppositely signed protons and electrons. Removing one of the negative electrons results in an excess of positively charged protons.
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115) What is one role of unpaired valance electrons?
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A) They take part in the formation of different types of bonds.
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116) Plastic wrap is made of nonpolar molecules and is able to stick well to polar surfaces, such as glass, by way of dipole/induced dipole molecular attractions. How is it that plastic wrap also sticks to itself so well?
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C) by way of induced dipole-induced dipole molecular attractions
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117) Which of the following bonds would be the least polar?
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A) C-H
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118) What it the main difference between an ionic and a covalent bond?
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C) One is the sharing of a pair of electrons, the other is the transfer of at least one electron.
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119) Two chemical structures are shown, one of a typical gasoline molecule and the other of a typical motor oil molecule. Which is which?
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B) Structure A represents motor oil, illustrating a molecule with greater induced dipole-induced dipole molecular interactions thus, the molecules are strongly attracted to one another.
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120) Why is metal shiny?
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C) The loose electrons reflect most wavelengths of light.
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121) How many chloride ions (Cl^-1) are needed to balance the positive charge of a barium ion (Ba^+2)?
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D) 2
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122) Which of the following compounds has polar covalent bonds?
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D) H2O
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123) Classify the following bonds as ionic, covalent, or neither (O, atomic number 8; F, atomic number 9; Na, atomic number 11; Cl, atomic number 17; U, atomic number 92).O with F Ca with Cl Na with Na
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A) covalent, ionic, neither
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124) Which of the following would have the smallest number of induced dipole-induced dipole interactions?
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A) C6H14
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125) Which of the following molecules would contain a dipole?
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B) H-F
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126) Which of the following compounds contains ionic bonds?
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A) K2O
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127) Which of the following molecules contains a polar bond?
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B) H-F
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128) What is the name for the following polyatomic ion? PO4^-3
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A) phosphate
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129) Which of the following is the strongest?
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D) a chemical bond
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130) What is the difference between a dipole-dipole interaction and an ion-dipole interaction?
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B) one involves dipole attraction between neutral molecules while the other involves dipole interactions with ions
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131) Why are ion-dipole attractions stronger than dipole-dipole attractions?
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A) The magnitude of the electric charge associated with an ion is much greater.
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132) In terms of the periodic table, is there an abrupt or gradual change between ionic and covalent bonds?
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B) There is a gradual change: the farther apart, the more ionic.
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133) Which should be larger, the potassium atom, K, or the potassium ion, K⁺?
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D) The potassium atom, K, with an additional shell of electrons is larger.
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134) If the following generic atom were to undergo ionization, what would the most likely product be? .. .. X .. ..
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E) would probably not ionize
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135) Why is the surface area of a geckoʹs foot so extensive?
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A) The greater the surface area the greater the number of induced dipole-induced dipole forces of attraction that can occur between the geckoʹs foot and the surface.
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136) Which of the following molecules would you expect to be the least attracted to a Na+ ion?
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E) H3C-CH3
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137) Which of the following is most likely to have the weakest induced dipole-induced dipole interaction?
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D) F2
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138) Which of the following describes how a metal atoms behaves in a bulk metallic object?
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C) The metal ion shares its outermost electrons freely with its neighbors.
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139) Which of the following statements is untrue?
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A) Covalent molecules are never crystalline.
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140) Which of the following molecules is the most polar?
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B) HCl
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141) How many valence electrons does boron (B, atomic no. = 5) have?
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C) 3
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142) Which of the following would be a negative ion with a single charge?
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D) an atom with 11 protons and 12 electrons
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143) Which of the following is the main form of intermolecular attractions among water molecules?
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D) hydrogen bonding
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144) Which of the following does not describe ionic compounds?
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D) They have a tendency to melt easily.
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145) Which of the following is a positive ion?
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E) all of the above(Al+3,Na+1,Mg+2,Ca+2)
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146) How many covalent bonds would the following atom usually form? . X .
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E) It would tend to form ionic bonds.
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147) Which of the following molecules would you expect to be the most strongly attracted to a Cl- ion?
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C) H-F
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148) Which are closer together: the two nuclei within potassium fluoride, KF, or the two nuclei within molecular fluorine, F2?
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B) F2
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149) Which of the following intermolecular forces best describes why nonpolar molecules like gasoline (C8H18) have only limited solubility in water?
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E) Both A and B( dipole-dipole,induced dipole-induced dipole)
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150) Metals are useful for the structural support of buildings because they
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C) are strong but can be bent.