Concept explainers
3-79 Answer true or false.
(a) The letters VSEPR stand for valence-shell electron-pair repulsion.
(b) In predicting bond angles about a central atom in a covalent molecule, the VSEPR model considers only shared electron pairs (electron pairs involved in forming covalent bonds).
(c) The VSEPR model treats the two electron pairs of a double bond as one region of electron density and the three electron pairs of a triple bond as one region of electron density.
(d) In carbon dioxide, OCO, carbon is surrounded by four pairs of electrons and the VSEPR model predicts 109.5° for the O−C−O bond angle.
(e) For a central atom surrounded by three regions of electron density, the VSEPR model predicts bond angles of 120°.
(f) The geometry about a carbon atom surrounded by three regions of electron density is described as trigonal planar.
(g) For a central atom surrounded by four regions of electron density, the VSEPR model predicts bond angles of 360°/4 = 90°.
(h) For the ammonia molecule, NH3, the VSEPR model predicts H−N−H bond angles of 109.5°.
(i) For the ammonium ion, NH4, the VSEPR model predicts H−N−H bond angles of 109.5°.
(j) The VSEPR model applies equally well to covalent compounds of carbon, nitrogen, and oxygen.
(k) In water, H−O−H, the oxygen atom forms covalent bonds to two other atoms, and therefore, the VSEPR model predicts an H−O−H bond angle of 180°.
(l) If you fail to consider unshared pairs of valence electrons when you use the VSEPR model, you will arrive at an incorrect prediction.
(m) Given the assumptions of the VSEPR model, the only bond angles it predicts for compounds of carbon, nitrogen, and oxygen are 109.5°, 120°, and 180°.
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Chapter 3 Solutions
Introduction To General, Organic, And Biochemistry
- 3-31 Why does electronegativity generally increase going from left to right across a row of the Periodic Table?arrow_forward3-105 Consider the structure of Vitamin E shown below, which is found most abundantly in wheat germ oil, sunflower, and safflower oils: (a) Identify the various types of geometries present in each central atom using VSEPR theory. (b) Determine the various relative bond angles as sociated with each central atom using VSEPR theory. (c) Which is the most polar bond in Vitamin E? (d) Would you predict Vitamin E to be polar or nonpolar?arrow_forward3-120 Vinyl chloride is the starting material for the production of poly(vinyl chloride), abbreviated PVC. Its recycling code is “V”. The major use of PVC is for tubing in residential and commercial construction (Section 12-7). (a) Complete the Lewis structure for vinyl chloride by showing all unshared pairs of electrons. (b) Predict the HCH, HCC, and ClCH bond angles in this molecule. (c) Does vinyl chloride have polar bonds? Is it a polar molecule? Does it have a dipole?arrow_forward
- 3-41 Describe the structure of sodium chloride in the solid state.arrow_forward3-67 Why does nitrogen have three bonds and one unshared pair of electrons in covalent compounds?arrow_forward3-70 Draw a Lewis structure of a covalent compound in which oxygen has: (a) Two single bonds and two unshared pairs of electrons (b) One double bond and two unshared pairs of electronsarrow_forward
- 3-64 Acetylene (C2H2), hydrogen cyanide (HCN), and nitrogen (N2) each contain a triple bond. Draw a Lewis structure for each molecule. Which of these are polar molecules, and which are nonpolar molecules?arrow_forward3-29 Answer true or false. (a) According to the Lewis model of bonding, atoms bond together in such a way that each atom participating in the bond acquires an outer-shell electron configuration matching that of the noble gas nearest to it in atomic number. (b) Atoms that lose electrons to achieve a filled valence shell become cations and form ionic bonds with anions. (c) Atoms that gain electrons to achieve filled valence shells become anions and form ionic bonds with cations. (d) Atoms that share electrons to achieve filled valence shells form covalent bonds. (e) Ionic bonds tend to form between elements on the left side of the Periodic Table, and covalent bonds tend to form between elements on the right side of the Periodic Table. (f) Ionic bonds tend to form between a metal and a nonmetal. (g) When two nonmetals combine, the bond between them is usually covalent. (h) Electronegativity is a measure of an atom’s at traction for the electrons it shares in a chemical bond with another atom. (j) Electronegativity generally increases with atomic number. (j) Electronegativity generally increases with atomic weight. (k) Electronegativity is a periodic property. (l) Fluorine, in the upper-right corner of the Periodic Table, is the most electronegative element; hydrogen, in the upper-left corner, is the least electronegative element. (m)Electronegativity depends on both the nuclear charge and the distance of the valence electrons from the nucleus. (n) Electronegativity generally increases from left to right across a period of the Periodic Table. (o) Electronegativity generally increases from top to bottom in a column of the Periodic Table.arrow_forward3-109 Until several years ago, the two chlorofluorocarbons (CFCs) most widely used as heat transfer media in refrigeration systems were Freon-li (trichloro fluoromethane, CC13F) and Freon-12 (dichiorodi fluoromethane, CCl2F2). Draw a three-dimensional representation of each molecule and indicate the Direction of it.s polarity.arrow_forward
- 3-127 Amoxicillin is an antibiotic used to treat bacterial infections caused by susceptible microorganisms. Consider the skeletal structure of amoxicillin (y refer to the structure at bottom of page). Where all the bonded atoms are shown but double bonds, triple bonds, and/or lone pairs are missing: (a) Complete the structure of amoxicillin. (b) Identify the various types of geometries present in each central atom using VSEPR theory (e) Determine the various relative bond angles as sociated with each central atom using VSEPR theory. (d) What is the most polar bond in Amoxicillin? (e) Would you predict amoxicillin to be polar or nonpolar? (f) Is amoxicillin expected to possess resonance? Explain why or why not. V Chemical structure for problem 3-127arrow_forward3-68 Draw a Lewis structure of a covalent compound in which nitrogen has: (a) Three single bonds and one unshared pair of electrons (b) One single bond, one double bond, and one unshared pair of electrons (c) One triple bond and one unshared pair of electronsarrow_forward3-122 Some of the following structural formulas are incorrect because they contain one or more atoms that do not have their normal number of covalent bonds. Which structural formulas are incorrect, and which atom or atoms in each have the incorrect number of bonds?arrow_forward
- Introduction to General, Organic and BiochemistryChemistryISBN:9781285869759Author:Frederick A. Bettelheim, William H. Brown, Mary K. Campbell, Shawn O. Farrell, Omar TorresPublisher:Cengage Learning