Advanced Chem: Worksheet on bonding: Lewis Dot Diagrams Page 1 1. Write the electron configuration for these ions. Which one(s) do not have a noble gas configuration? Ba+2 I– Fe+2 Zr+4 Au+3 Se–2 2. Explain the following trends in lattice energy: a. CaS>KCl b. LiF>CsBr c. MgO>MgS 3. Check your handout and !H chart for values needed for this question. a. Use the Born Haber cycle to calculate !Hf° for KI(s) (–328 kJ/mol) . b. An approximate value for the lattice energy for a hypothetical compound KI2 is 1900 kJ/mol. Show calculations to explain why this compound doesn’t form. 4. Write the Lewis (dot) diagrams for the following molecular compounds or polyatomic ions. H2S PH3 OF2 CCl4 CHClF2 (freon) CO H3CCH3 H2CCH2 HCCH CH2O (C is central) ethane ethene ethyne (formaldehyde) OH– hydroxide NH2– BrO2– ion amide ion bromite ion 1. Fe+2 , Au+3 ; 2. a +2 vs. +1, b& c. smaller size. on back 5. a, g = odd; c = less, b, d, e, f, h = more; 6. O 4 (cont). Write Lewis diagrams for the following polyatomic ions. Page 2 SO3–2 CN- NH4+ sulfite ion cyanide ion ammonium ion 5. Write the Lewis structures for the following species and explain how they violate the octet rule. (odd number of electrons, less than an octet, more than an octet). a. NO2 b. TeF4 c. BCl3 d. XeF4 e. I3– f. AsF6– g. O2– h. ICl3 6. Which of the following can not have more than an octet? Why not? Ar O Cl Br 7. Draw resonance structures for each of the following: SO3 ClO3 (hint: move the odd electron) CO3–2 NO2– Bond energies (covalent) 8. Which of the following bonds is the most stable? (highest bond energy) Least stable? C–H C– O C–F C–I 9. Which of the following bonds would be the shortest? C–C C=C C! O 10. Using Bond Energies, estimate !H for this gas phase reaction. (Bonds broken – bonds made) C! O + H–O–H –––> H–H + O=C=O (–36 kJ) 11. Photons of EM radiation can break chemical bonds. What is the longest wavelength of light that can break a Cl–Cl bond (242 kj/mol)? Can you see it? Hint: First change kJ/mol of bonds to J/bond. (494 nm) Adv Chem Bonding worksheet: Part 2 Page 3 1. Identify these bonds as non-polar (eneg. diff = 0 to 0.2), polar (0.21 to 1.8) or ionic (above 1.8)? In the polar bonds, identify the ! + and ! – element of each. Which bond is the most polar (but not ionic)? Electronegativities are on the back of your periodic table. a. B–Cl b. Cl–Cl c. As–O d. Na–Cl e. C–Br 2. The molecules NF3, BF3, and ClF3 all have molecular formulas of the type XF3 but have different molecular geometries. Write the dot diagrams and predict the shape for each. Why are their shapes different? 3. You did the Lewis diagrams for these molecules and ions on the previous worksheet. Use them to fill in the following table. # e– Electron pair bond. non– Molecular Hybrid Polar/NP pairs geometry e– bond e– geometry orbitals molecule? ex. SF4 5 Trigonal 4 1 Seesaw sp3d polar bipyramidal a. CClHF2 b. PH3 c. H2S d. CH2O e. TeF4 f. BCl3 g. XeF4 h. I3– i. AsF6– j. ICl3 k. SO3 1. a, c, e = P (c most); b= NP; d= I; 2. Trig Pyramidal, Trig Planar, T-shaped; 3. a. tetra./tetra, sp3, P; b. tetra/ trig. pyramid, sp3, NP; c. tetra/bent, sp3, P; d. trig planar/trig. planar, sp2, P; e. trig. bipyramid./seesaw, sp3d, P; f. trig. planar/trig planar, sp2, NP; g. octa./sq. planar, sp3d2, NP; h. trig. bipyramid./ linear, sp3d, NP; i. octa/octa, sp3d2, NP, j. trig, bipyramid, T-shaped, sp3d, P; k. trig.planar/trig planar, sp2, NP 4. Describe the hybridization of the Carbon (and Oxygen) atoms in these molecules. Page 4 How many sigma and pi bonds are there in the molecules? H H HH C1 ____ C2 ____ C3 ____ C4 ____ | | | | C5 ____ C6 ____ sp3, sp3,sp, sp, H–C–C–C"C–C=C–H sigma bonds = _____ sp2, sp2, 13, 3; | | pi bonds = _____ H H HH H O1 ____ C1 ____ C2 ____ C3 ____ .. | | | .. C4 ____ C5 ____ C6 ____ H–O–C=C–C "C–C=C=O sigma bonds = _____ sp3, sp2, sp2, sp, sp, ˙˙ ˙˙ pi bonds = _____ sp2, sp, 11, 5 5. Fill in Molecular Orbital energy level diagram for these species and calculate their bond order. Bond order = 1 (bonding e- – antibonding e-) (Yes, they can have “1”) Then predict the magnetic properties for each: paramagnetic = unpaired electrons (attracted to magnetic field), diamagnetic = all electrons are paired (weakly repelled by magnetic field). CO CN– NO O2 O2– #*2p ____ ____ ____ ____ ____ $ *2p ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ # 2p ____ ____ ____ ____ ____ $ 2p ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ #*2s ____ ____ ____ ____ ____ # 2s ____ ____ ____ ____ ____ Bond order____ ____ ____ ____ ____ Mag. prop. ____ ____ ____ ____ ____ Experimentally, NO molecules fairly easily make NO+ ions. Explain this result using your Molecular Orbital diagram. O2–2 Ne2 Ne2+ Li2 Li2 –2 #*2p ____ ____ ____ ____ ____ $ *2p ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ # 2p ____ ____ ____ ____ ____ $ 2p ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ #*2s ____ ____ ____ ____ ____ # 2s ____ ____ ____ ____ ____ Bond order____ ____ ____ ____ ____ Mag prop ____ ____ ____ ____ ____ Stable? (Yes/no) ___ ____ ____ ____ ____ Experimentally, superoxide ion, O2–, has a shorter bond length than the peroxide ion, O2–2. Explain this experimental result using your MO diagrams. Which bond would be a bit “stronger?” AP Chem Bonding Worksheet: Organic molecules Page 5 . 1. Here are 3 structural isomers of pentane, C5H12 . H HH \|/ H HH H H H HH H C H iso -pentane | | | | | \|/ \ | / <––– H–C–C–C–C–C–H H CH H H–C– C–C–H | | | | | | | | | / | \ H HH H H H–C–C–C–C–H neo- pentane–––> H C H | | | | /|\ n-pentane H HH H H HH a. Are these molecules Polar or Non-polar? Why do you think so? b. Which is a “straight chain”? __________ Which are “branched chains?” ______________ c. Which would you predict to have the greatest intermolecular attraction (and hence the highest Boiling Point?) ______________ The lowest? ___________________ Why? 2. Here are 4 structural isomers of C4H8O. A. Circle any Carbons with sp2 hybridization. B. Which of these molecules has cis and trans isomers? C. Which one(s) are Polar? D. Which of these molecules would have hydrogen bonding? Put a box around the applicable parts of the molecule(s). E. Which would probably dissolve in water? Why? F. Which would probably have the highest Boiling point? Why? a H HH H b H H H c H H H d H HH | | | | | | | | | | | | | H–C–C–C–C=O H–C–C=C–C–O–H H–C–C–C–C–H H–C=C–O–C–C–H | | | | | | | | | | | | | H HH H H H H OH H H HH 1. a. NP, all C’s Hs’; b. n=straight; iso&neo= branched; c. n- highest, neo lowest; straight= more attraction; 2. A. a=C4 , b=C2 &C3, c=C2 , d =C1 &C2 ; B. b only; C. a, b, c; D. b only (H bonded to O); E. a, b, c, Polar; F. b, hydrogen bonding is “strong”. Page 6 3. A. Which of the following molecules would have Hydrogen bonding? Circle applicable parts of the molecule(s). _______________ Label Carbons with sp hybridization, sp2 hybridization and sp hybridization. Label tetrahedral Carbons, Trigonal planar C’s and Linear C’s e a H HH b c Br H d HH O H H | | | \ / | | || \ / Cl–C–C–C–O–H Br–C ! C–H C=C Cl–C–C–C–O–H C=C=C | | | / \ | | / \ H HH H Br H H Cl Cl 4. What’s wrong with the following molecules? (more than 1 thing in some) a H HH H b Br H c H HH | | | | \ / | | | H–C=C–C–O–H–C–H C = C– H H=C–C–C!O=C–H | | | | / \ | | H ClH H H H Cl H 5. Draw 3 isotopes of C8H12O2 that has: a. Has a “branched chain” and would not have Hydrogen bonding. b. Has a Carbon with sp hybridization, and would have Hydrogen bonding c. Has a “branched chain” and at least one C to O double bond . 3. A. a, d; B. sp=b, e, sp2 = c, d, e ; sp3 = a, d ; 4. a. 5 bonds around 1st&2nd C,2 on H ; b. 5 on 2nd C; c. 2 on 1st H, 5 on 3rd C, 4 on O, 3 on 4th C .
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