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CHM 1010 COVALENT COMPOUNDS CHAPTER 4 CONCEPT
QUESTIONS WITH CORRECT ANSWERS (ALL QUESTIONS )
1.A _____ is a discrete group of atoms held together by covalent bonds. - molecule 2.A _________ _____________ shows all of the bonds and nonbonding electrons, but a ____________ _________ does not. – Blank 1: Lewis Blank 2: structure Blank 3: molecular or chemical Blank 4: structure or formula 3.A covalent bond is a _____-electron bond in which the bonding atoms share their _____ electrons. - two; valence 4.A covalent bond results from the sharing of electrons between/among _____ atoms. - two 5.A mixture of dimethyl ether and propane is used in an over-the-counter device to treat warts, by freezing them. The structure of dimethyl ether is shown. Is dimethyl ether a polar or nonpolar molecule? - Polar Reason: There is a partial negative charge on the oxygen atom and partial positive charges on the carbon atoms. These dipoles do not cancel each other because the geometry around the oxygen is bent. 6.An atom with a bent shape is surrounded by _____ atoms and _____ lone pair(s) of electrons - two; one two; two 7.An atom with a tetrahedral shape is surrounded by ______ atoms or groups. - four Covalent compounds are formed by _____, - sharing electrons between atoms Electronegativity measures - an atom's attraction for electrons in a bond. How many bonds will boron typically form? - 3
How many covalent bonds are there in the molecule of SO2 whose structure is shown? - 3 How many covalent bonds are there in the structure shown? - 6 How many electrons are contained in a complete octet of electrons? - 8 How many electrons does boron typically have in its valence shell when it is the central atom in a Lewis structure? - 6 How many lone pairs of electrons need to be added to the Lewis structure shown?- 0 - 9 - 11 - 18 - 9 How many resonance structure are needed to describe the structure of HNO3? - 2 How many valence electrons are in CH3NH2? - 14 How many valence electrons are in PO33-? - 26 In order for a bond to be nonpolar, the difference in electronegativities of the two atoms is _____. - <0. In the Lewis structure of CHBr3 the central atom is the _____. - carbon In the molecule shown, which of the following are in the plane of the paper? - H O of the OH group C List the atoms in order of decreasing electronegativity. (Place the lowest electronegativity at the bottom.) - o ,s, se ,te List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the bottom.) - Na Al P S List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the bottom.) - Na, Al, P, S List the common prefixes in order of increasing number of atoms. (Place the largest number of atoms on the bottom.) - Tri, penta, hepta, nona, List the elements below in order of increasing electronegativity. - K
Nitrogen- 3 Oxygen- 2 Chlorine- 1 Match the atom with with the number of lone pairs of electrons it will commonly possess in a Lewis structure. - Carbon- 0 Nitrogen- 1 Oxygen- 2 Chlorine- 3 Match the molecular geometry and the number of lone pairs of electrons on the central atom. - Trigonal planar geometry--- 0 Trigonal pyramid geometry---Only 1 Bent geometry---1 or 2 Nitrogen will bond so as to attain the electronic configuration of - neon, Ne, or 2s^2 2p^ Ozone, O3, exists as a composite, or hybrid, of the two resonance structures shown. How does the resonance hybrid stabilize the ozone molecule? - Resonance spreads lone pairs and double bonds over a larger area. Ozone, O3, exists as more than one resonance structure; that is, more than one valid Lewis structure of the molecule can be drawn. Which of the structures shown are valid resonance forms of ozone? - A B Rank the atoms in descending order of the number of bonds that they commonly form. Place the element at the top that forms the most bonds. - C, P, S, Br Rank the bonds listed below in order of increasing polarity. Place the most polar bond at the bottom. - N-N N-O N-H N-F Select all of the polar molecules from the formulas shown. - CHCl SO O=C=S The _____ an atom's electronegativity, the _____ it "wants" shared electrons. - higher; more The Lewis structure of C3H8 shown contains _______ nonbonded electron pairs. Enter your answer as a number. - 0 or zero The Lewis structure of SO2 shown contains nonbonded electron pairs. Enter your answer as a number. - 6 or six
The resonance structures of ozone _____. - differ in the placement of a double bond and a lone pair True or False: All exceptions to the octet rule describe atoms that have less than an octet of electrons in molecules. - False True or False: Polar bond and polar covalent bond are synonymous terms. - True True or false: The Lewis structure shown is a complete and valid Lewis structure. - False True or False: When atoms share electrons, they share so as to attain the electronic configuration of the closest noble gas in the periodic table. - True Two resonance forms (shown) can be drawn for sulfur dioxide, SO2. Which statement below correctly describes the actual structure of SO2? - SO2 exists as a composite of the two resonance structures. What are the bond angles in a linear structure? - 180o What are the bond angles in a trigonal planar structure? - 120o What are the bond angles in a trigonal pyramid geometry? - < 109.5o What are the bond angles in a trigonal pyramid geometry? - < 109.5o What is the correct name for SiO2? - silicon dioxide What is the correct name of SF6? - sulfur hexafluoride What is the major beneficial effect of the presence of ozone (O3) in Earth's upper atmosphere? - Ozone absorbs harmful UV radiation. When can a molecule that contains polar bonds be nonpolar? - When individual bond dipoles cancel When counting the number of valence electrons in a cation, _____ an electron for each _____ charge. - subtract; positive When drawing a Lewis structure, form multiple bonds when _____. - an atom does not have an octet and an adjacent atom has at least one lone pair of electrons When is a numerical prefix not usually used in naming a covalent compound containing two elements? - When there is only one atom of the first element Which atom has the smallest electronegativity? - Cs
Phosphorus - Carbon Phosphorous Calcium Which elements typically possess two lone pairs of electrons in a Lewis structure? (Select all that apply.) Phosphorus, Carbon, Sulfur, Oxygen - Sulfur Oxygen Which is a resonance structure of the top structure? - D Which is the correct Lewis structure for chloroethylene (C2H3Cl)?- A- B- C- D - C Which Lewis structures shown are not possible? Select all that apply. - B D Which of the bonds listed below are polar? Select all that apply. - C-F H-Cl Which of the following are covalent molecules in living organisms? - hemoglobin protein water DNA Which of the following are examples of consumer uses of hydrogen peroxide, H2O2? Select all that apply. - Disinfecting wounds Whitening teeth Which of the following covalent substances are typically found in living systems? Select all that apply. - Proteins Carbohydrates Fats Which of the following elements typically form covalent bonds?
- oxygen
- fluorine
- barium
- aluminum
- carbon - Fluorine Carbon Oxygen Which of the following elements typically form covalent bonds? (Select all that apply.) - Oxygen Carbon Fluorine
Which of the following is shown in a Lewis structure, but not in a molecular formula? - Which atoms are bonded to each other Where the nonbonding valence electrons reside Which of the following molecules and ions have resonance structures? - CO32- SO Which of the following molecules are polar? - HCN NH FCH Which of the following molecules contain 16 valence electrons? (Select all that apply.) - N2O CO C3H Which of the following molecules have a bent geometry? - SO H2S O Which of the following molecules have a bent geometry? - SO H2S O Which of the following molecules have a linear geometry? - HCN CO Which of the following molecules have a trigonal pyramidal geometry? - NH PF Which of the following molecules have tetrahedral shape? - NH4+ CH2Cl Which of the following names are not correct? - carbon terpachloride monosulfur trioxide nitrogen trichlorine Which of the following species have a trigonal planar geometry? - H2C=O SO CO32- Which of the following statements about molecular polarity are correct? Select all that apply. - A polar molecule must contain a polar bond. A nonpolar molecule can contain three polar bonds. Which of the following statements correctly describe covalent compounds? Select all that apply.
- Most of the compounds that we come in contact with are covalent compounds.
Covalent compounds contain covalent bonds. A covalent bond results from the sharing of electrons between/among _____ atoms. - two Which of the substances listed below exist as molecules? Select all that apply. - HF N H2O How many covalent bonds are there in the structure shown? - 6 The Lewis structure of SO2 shown contains nonbonded electron pairs. Enter your answer as a number. - 6 or six Covalent compounds are formed by _____, - sharing electrons between atoms A covalent bond is a _____-electron bond in which the bonding atoms share their _____ electrons. - two; valence True or False: When atoms share electrons, they share so as to attain the electronic configuration of the closest noble gas in the periodic table. - True A _____ is a discrete group of atoms held together by covalent bonds. - molecule How many electrons are contained in a complete octet of electrons? - 8 How many covalent bonds are there in the molecule of SO2 whose structure is shown? - 3 Which of the following elements typically form covalent bonds?
- oxygen
- fluorine
- barium
- aluminum
- carbon - Fluorine Carbon Oxygen The Lewis structure of C3H8 shown contains _______ nonbonded electron pairs. Enter your answer as a number. - 0 or zero Which of the following statements correctly describe covalent compounds? Select all that apply.
- Most of the compounds that we come in contact with are covalent compounds. Covalent compounds contain covalent bonds. Covalent compounds are formed by sharing electrons between atoms. How many bonds will boron typically form? - 3
Nitrogen will bond so as to attain the electronic configuration of - neon, Ne, or 2s^2 2p^ Match the atom with the number of bonds it will commonly form. - Carbon- 4 Nitrogen- 3 Oxygen- 2 Chlorine- 1 Which elements listed below are most stable when they possess an octet of electrons in their outer shell? (Select all that apply.) Iron Calcium Carbon Hydrogen Phosphorus - Carbon Phosphorous Calcium Which elements typically possess two lone pairs of electrons in a Lewis structure? (Select all that apply.) Phosphorus, Carbon, Sulfur, Oxygen - Sulfur Oxygen Which types of elements generally form covalent bonds? (Select all that apply.) - metalloids nonmetals Which of the following are covalent molecules in living organisms? - hemoglobin protein water DNA Match each element on the left with the number of covalent bonds that it will typically form. - H- 1 Mg- 2 B- 3 A _________ _____________ shows all of the bonds and nonbonding electrons, but a ____________ _________ does not. - Blank 1: Lewis Blank 2: structure Blank 3: molecular or chemical Blank 4: structure or formula Rank the atoms in descending order of the number of bonds that they commonly form. Place the element at the top that forms the most bonds. - C, P, S, Br Which statement about electrons in Lewis structures is correct? - Only the valence electrons are drawn in a Lewis structure
- Chlorine Which is the correct Lewis structure for chloroethylene (C2H3Cl)?- A- B- C- D - C How many valence electrons are in CH3NH2? - 14 Which elements can violate the octet rule? - H B S Which element listed below can form stable molecules with only six electrons in its valence shell? - Boron 3A - boron atom has three valence electrons, so it forms only three bonds, totaling six electrons. True or false: The Lewis structure shown is a complete and valid Lewis structure. - False Which Lewis structures shown are not possible? Select all that apply. - B D When drawing a Lewis structure, form multiple bonds when _____. - an atom does not have an octet and an adjacent atom has at least one lone pair of electrons Which of the structures shown are valid Lewis structure? - B C D How many valence electrons are in PO33-? - 26 True or False: All exceptions to the octet rule describe atoms that have less than an octet of electrons in molecules. - False Which of the following molecules and ions have resonance structures? - CO32- SO How many electrons does boron typically have in its valence shell when it is the central atom in a Lewis structure? - 6 Which is a resonance structure of the top structure? - D Which elements can violate the octet rule by having more than eight electrons around them? - Sulfur Phosphorous Which atom is least likely to form a multiple bond? Multiple choice question. Oxygen - Hydrogen
Ozone, O3, exists as a composite, or hybrid, of the two resonance structures shown. How does the resonance hybrid stabilize the ozone molecule? - Resonance spreads lone pairs and double bonds over a larger area. When counting the number of valence electrons in a cation, _____ an electron for each _____ charge. - subtract; positive The resonance structures of ozone _____. - differ in the placement of a double bond and a lone pair How many resonance structure are needed to describe the structure of HNO3? - 2 Which of the following statements correctly describe resonance and resonance structures? - The only difference between resonance structures is the position of the electrons. Resonance stabilizes a molecule by spreading out electrons over a larger region of space. What is the major beneficial effect of the presence of ozone (O3) in Earth's upper atmosphere? - Ozone absorbs harmful UV radiation. Which of the following names are not correct? - carbon terpachloride monosulfur trioxide nitrogen trichlorine Two resonance forms (shown) can be drawn for sulfur dioxide, SO2. Which statement below correctly describes the actual structure of SO2? - SO2 exists as a composite of the two resonance structures. Ozone, O3, exists as more than one resonance structure; that is, more than one valid Lewis structure of the molecule can be drawn. Which of the structures shown are valid resonance forms of ozone? - A B List the common prefixes in order of increasing number of atoms. (Place the largest number of atoms on the bottom.) - Tri, penta, hepta, nona, What is the correct name of SF6? - sulfur hexafluoride Which of the following statements correctly describe ozone? - Ozone absorbs harmful ultraviolet radiation. Ozone is formed in the stratosphere. Match each molecular formula with its correct geometry. A. H2C=O B. COS (C is the central atom) C. So2 (Sis the central atom)
CH2Cl Match the molecular geometry and the number of lone pairs of electrons on the central atom. - Trigonal planar geometry--- 0 Trigonal pyramid geometry---Only 1 Bent geometry---1 or 2 Match each molecular formula with its correct geometry. - H2C=O---Trigonal planar geometry COS (C is the central atom.)---Linear geometry SO2 (S is the central atom.)---Bent geometry PH3-----Trigonal pyramid The _____ an atom's electronegativity, the _____ it "wants" shared electrons. - higher; more In the molecule shown, which of the following are in the plane of the paper? - H O of the OH group C Which of the following molecules have a trigonal pyramidal geometry? - NH PF An atom with a bent shape is surrounded by _____ atoms and _____ lone pair(s) of electrons - two; one two; two List the molecular geometries in order of increasing bond angles. (Place the largest bond angles at the bottom.) - Trigonal pyramid tetrahedral trigonal planar Linear List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the bottom.) - Na Al P S Electronegativity measures - an atom's attraction for electrons in a bond. List the atoms in order of decreasing electronegativity. (Place the lowest electronegativity at the bottom.) - o ,s, se ,te List the elements below in order of increasing electronegativity. - K
Ge As Br What are the bond angles in a trigonal pyramid geometry? - < 109.5o Which of the following molecules have a bent geometry? - SO H2S O In order for a bond to be nonpolar, the difference in electronegativities of the two atoms is _____. - <0. Which atoms have a higher electronegativity than carbon? - O N F Which atoms have a higher electronegativity than arsenic (As)? - P N Which of the bonds listed below are polar? Select all that apply. - C-F H-Cl Which atom has the smallest electronegativity? - Cs Which of the following statements correctly describe the nature of a dipole? - A dipole is a separation of charge. A dipole is generated when there is a significant difference in electronegativity between the two atoms in a bond. When can a molecule that contains polar bonds be nonpolar? - When individual bond dipoles cancel Which bonds listed below are nonpolar? - F-F C-C C-S Which of the following molecules are polar? - HCN NH FCH List the atoms in order of increasing electronegativity. (Place the highest electronegativity at the bottom.) - Na, Al, P, S
