Station 1-Lewis Structures
For the following formulas, complete the following: A. Draw the complete Lewis structure B. Electronic Domain Geometry C. Molecular Geometry D. Polarity E. Dissolves in water? F. Force (Dipole, Hydrogen bond, London)
1. -1 PS3 2. BH3 3. SF2 4. CS2 5. CH3I Station 2- Properties & Macromolecules
1. What is the difference between an ionic bond and a covalent bond? 2. A bond (shared pair) represents how many electrons? 3. Explain why ionic compounds do not conduct electricity in their crystalline (solid) structure. 4. Given the following properties, would you list the compound as ionic or not ionic. a. Compound 1 has a melting point of 545 degrees Celsius and dissolves well in water. b. Compound 2 is a brittle material that is used to melt road ice during storms. 5. What is the difference between a cation and an anion? 6. What makes a single bond weaker than a double or triple bond? 7. How do the VSEPR theory and molecular geometry relate? 8. Proteins in the body are made from the linking of ______. ______is an example of protein found in hair and nails. 9. A polymer is a structure made of 2 or more types of ______. What is an example of a polymer? 10. Network Covalent Bonds have no intermolecular forces and are made of carbon bonds. Graphite and diamonds are examples of NCB’s. Even though these bonds are very strong, what about graphite’s structure makes it weaker than a diamond? 11. How are boiling points affected by intermolecular forces? 12. Give an explanation in terms of Intermolecular Forces for the following differences in boiling point. a) HF (20oC) and HCl (-85oC) b) CHCl3 (61oC) and CHBr3 (150oC) c) Br2 (59oC) and ICl (97oC) 13. Which of the following is expected to have the highest boiling point?
a) CO2 b) Ar c) CF4 d) LiCl e) SiF4 Station 3- Ionic Nomenclature
Name the following ionic compounds.
1. NH4Cl
2. Fe(NO3)3
3. TiBr3
4. Cu3P
5. SnSe2
6. GaAs
7. Pb(SO4)2
8. Be(HCO3)2
9. Mn2(SO3)3
10. Al(CN)3
Write the formulas for the following ionic compounds.
11. Chromium (VI) phosphate
12. Vanadium (IV) carbonate
13. Tin (II) nitrite
14. Cobalt (III) oxide
15. Titanium (II) acetate
16. Vanadium (V) sulfide
17. Chromium (III) hydroxide
18. Lithium iodide
19. Lead (II) nitride
20. Silver bromide Station 4- Covalent Nomenclature
Write the formulas for the following covalent compounds. 1. disulfur tetrafluoride 2. carbon trioxide 3. nitrogen pentoxide 4. nitrogen tribromide 5. dinitrogen heptachloride 6. carbon tetrachloride 7. hydrogen monochloride 8. trihydrogen monophosphide 9. dihydrogen monoxide
Name the following covalent compounds.
10. N2O3
11. P2O5
12. TeBr2
13. C3N4 14. OS
15. CI4
16. PF5 17. NP
18. SCl2 Answers Station 1, 3 and 4- on paper
Station 2 1. Ionic- bond between a metal and a nonmetal. Covalent- bond between a nonmetal and a nonmetal Electrons are transferred in an ionic bond; they are shared in a covalent bond. Ionic bonds are usually polar while covalent bonds can be polar or nonpolar. Ionic bonds have higher melting/boiling points than covalent. 2. Two 3. Electricity can only be conducted when ions are moving. In their crystalline form, the ions in the ionic compound are locked tightly in one place.
4. a. The high melting point points toward an ionic compound, though the fact that it dissolves is irrelevant. b. This is ionic. The brittleness points toward this, though the road ice thing doesn’t really give any useful information. 5. Cation: positively charged ion Anion: negatively charged ion 6. A single bond is longer than a double or triple bond which makes it easier to break. As you add more bonds the shorter they become because they pull the atoms closer. 7. VSEPR Theory- Valence Shell Electron Pair Repulsion Theory (electron pairs around the central atom arrange themselves in such a way so as to minimize electron repulsion…try to get away from each other). This creates different shapes. 8. Amino Acids Keratin 9. Monomers; examples include nylon, plastic, proteins, rubber 10. Graphite’s bonds form into thin sheets stacked on each other that can slide across one another. A diamond’s structure is a completely connected network. This interconnecting is what makes it stronger than graphite. 11. Stronger intermolecular forces between molecules make it more difficult for those molecules to be pulled apart. Therefore, stronger intermolecular forces result in higher boiling points.
12. a) Both are polar. HF has hydrogen bonding, which is a stronger force, so it will have the higher boiling point. b) Both are polar and would have dipole-dipole interactions. In this case, we can compare LDF instead.
CHBr3 has more electrons, so it has the higher boiling point.
c) Br2 is nonpolar and has only LDF. ICl is polar and has dipole-dipole interactions, so it will have the higher boiling point. 13. Rank these substances from lowest to highest intermolecular forces a) CO2 b) Ar c) CF4 d) LiCl e) SiF4 nonpolar; LDF nonpolar; LDF nonpolar; LDF ionic nonpolar; LDF
LiCl is ionic and is expected to have the highest boiling point. The other substances are all limited to LDF, so they’re ranked based on number of electrons (CO2 = 22, Ar = 18, CF4 = 42, SiF4 = 50). Ar has the fewest electrons, so it has the weakest LDF and therefore the lowest boiling point.