front 1 How is a single covalent bond formed? | back 1 Two atoms share two electrons. |
front 2 You are asked to indicate the type and number of atoms in a molecule. Which representation would work best? | back 2 molecular formula |
front 3 Nitrogen (N) normally forms three covalent bonds with a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). What do you predict to be the charge on ammonium? | back 3 +1 |
front 4 When the atoms involved in a covalent bond have the same electronegativity, what type of bond results? | back 4 a nonpolar covalent bond |
front 5 An atom has four electrons in its valence shell. What types of covalent bonds is it capable of forming? | back 5 single, double, or triple |
front 6 Elements found on the left side of the periodic table contain outer shells that are ________; these elements tend to form ________ in solution. | back 6 almost empty; cations |
front 7 If an atom has a charge of +1, which of the following must be true? | back 7 It has one more proton than it does electrons. |
front 8 Refer to the following figure to answer the questions below. | back 8 sulfur |
front 9 Refer to the following figure to answer the questions below. | back 9 6 |
front 10 Refer to the following figure to answer the questions below. | back 10 the shape of the sp3 hybrid orbitals of the electrons shared between the carbon and hydrogen atoms |
front 11 Refer to the following figure to answer the questions below. | back 11 11 |
front 12 Refer to the following figure to answer the questions below. | back 12 a cation with a net charge of +1 and an anion with a net charge of -1 |
front 13 What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms? | back 13 six |
front 14 Van der Waals interactions may result when ________. | back 14 electrons are not symmetrically distributed in a molecule |
front 15 Which of the following is broken when water evaporates? | back 15 hydrogen bonds |
front 16 Which bond or interaction would be difficult to disrupt when compounds are put into water? | back 16 covalent bonds between carbon atoms |
front 17 How many electron pairs are shared between carbon atoms in a molecule that has the formula C2H4? | back 17 two |
front 18 The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride? | back 18 MgCl2 |
front 19 What is the difference between covalent bonds and ionic bonds? | back 19 Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms. |
front 20 A covalent bond is likely to be polar when ________. | back 20 one of the atoms sharing electrons is more electronegative than the other atom |
front 21 In the following structure where A and B represent two different elements, the valency of A is ________ and B is ________. | back 21 one; three |
front 22 Bonds between two atoms that are equally electronegative are ________. | back 22 nonpolar covalent bonds |
front 23 Nitrogen (N) is more electronegative than hydrogen (H). Which of the following is a correct statement about the atoms in ammonia (NH3)? | back 23 Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge. |
front 24 What is the maximum number of covalent bonds that an oxygen atom with atomic number 8 can make with hydrogen? | back 24 2 |
front 25 A covalent chemical bond is one in which ________. | back 25 outer-shell electrons of two atoms are shared so as to satisfactorily fill their respective orbitals |
front 26 Which one of the atoms shown would be most likely to form an anion with a charge of -1? | back 26 one with 9 electrons |
front 27 Which one of the atoms shown would be most likely to form a cation with a charge of +1? | back 27 one with 3 electrons |
front 28 A salamander relies on hydrogen bonding to stick to various surfaces. Therefore, a salamander would have the greatest difficulty clinging to a ________. | back 28 surface of hydrocarbons |
front 29 When are atoms most stable? | back 29 when all of the electron orbitals in the valence shell are filled |
front 30 Which of the following is the best description of an atom's physical structure? | back 30 Atoms are little bubbles of space with mass concentrated at the center of the bubble. |
front 31 Can the atomic mass of an element vary? | back 31 Yes. Adding or losing neutrons will change the atomic mass without forming a different element. |
front 32 Elements 72Zn, 75As, and 74Ge have the ________. | back 32 same number of neutrons |
front 33 Oxygen has an atomic number of 8 and, most commonly, a mass number of 16. Thus, what is the atomic mass of an oxygen atom? | back 33 approximately 16 daltons |
front 34 Refer to the following figure to answer the questions below. | back 34 6 |
front 35 Refer to the following figure to answer the questions below. | back 35 12 |
front 36 Refer to the following figure (first three rows of the periodic
table) to answer the questions below. | back 36 nitrogen and phosphorus |
front 37 efer to the following figure (first three rows of the periodic table)
to answer the questions below. | back 37 helium |
front 38 In a chemical reaction, the element 13Al will most preferably ________. | back 38 lose three electrons and become positively charged |
front 39 A neutral atom has two, eight, eight electrons in its first, second, and third energy levels. This information ________. | back 39 does not tell us about the atomic mass of the element |
front 40 The left to right order of elements in the periodic table is based on their ________. | back 40 atomic number |
front 41 The atomic number of nitrogen is 7. Nitrogen-15 has a greater mass number than nitrogen-14 because the atomic nucleus of nitrogen-15 contains ________. | back 41 8 neutrons |
front 42 A(n) ________ has charge but negligible mass, whereas a(n) ________ has mass but no charge. | back 42 electron; neutron |
front 43 Carbon-14 has the same ________. | back 43 number of protons but more neutrons than carbon-12 |
front 44 Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers from 92-100. Which of the following can be true? | back 44 Molybdenum atoms can have between 50 and 58 neutrons. |
front 45 An ion with six protons, seven neutrons, and a charge of 2+ has an atomic number of ________. | back 45 six |
front 46 Atoms have no electric charge because they have ________. | back 46 an equal number of protons and electrons |
front 47 Which of the following are compounds? | back 47 H2O and CH4, but not O2 |
front 48 Which of the following statements is TRUE? | back 48 Some naturally occurring elements are toxic to organisms. |
front 49 Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants? | back 49 iodine |
front 50 About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter? | back 50 carbon, hydrogen, nitrogen, oxygen |