Chemistry Answer Key PDF
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This document is a chemistry answer key focusing on ionic and covalent compounds, as well as Lewis structures. It contains multiple-choice and short-answer questions, with detailed explanations for each answer.
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# Answer Key ## 1. Draw in the valence shell electrons for the atoms below. - O - Al - Be Which of the above atoms donates electrons when forming an ionic bond? Al & Be Which of the above atoms accepts electrons when forming an ionic bond? O ## 2. Identify the charges of the following ions and...
# Answer Key ## 1. Draw in the valence shell electrons for the atoms below. - O - Al - Be Which of the above atoms donates electrons when forming an ionic bond? Al & Be Which of the above atoms accepts electrons when forming an ionic bond? O ## 2. Identify the charges of the following ions and determine if they are metals or nonmetals. | Element/Ion | Charge | Metal or Nonmetal | |---|---|---| | Potassium | +1 | Metal | | Arsenic/Arsenide | -3 | Nonmetal | | Iodine/Iodide | -1 | Nonmetal | | Barium | +2 | Metal | ## 3. Draw the Lewis Structure when Na and F combine to form an ionic compound. \[Na]^+ [F]^- ## 4. Draw the Lewis Structure when Ca and N combine to form an ionic compound. \[Ca]^{+2} [N]^{-3} ## 5. Classify each compound as ionic or covalent | Compound | Type | |---|---| | CaS | Ionic | | PBr<sub>3</sub> | Covalent | | CH<sub>4</sub> | Covalent | | Al(OH)<sub>3</sub> | Ionic | ## 6. Form a balanced ionic compound for the compounds listed. - a. SrF<sub>2</sub> - b. Ga<sub>2</sub>Se<sub>3</sub> - c. K<sub>2</sub>S ## 7. Name the following ionic compounds. - ScCl<sub>3</sub>: Scandium Chloride - CaBr<sub>2</sub>: Calcium Bromide - Al<sub>2</sub>O<sub>3</sub>: Aluminum Oxide - KOH: Potassium Hydroxide ## 8. Name the following covalent compounds - CCl<sub>4</sub>: Carbon Tetrachloride - P<sub>4</sub>S<sub>7</sub>: Tetraphosphorus heptasulfide ## 9. Draw a lewis structure of the following compound: CF<sub>4</sub> [F-C-F with single bonds between C and each F. Each F and C has two lone pairs.] Carbon forms 4 bonds and has 0 lone pairs. Each fluorine forms 1 bond and has 3 lone pairs. ## 10. Draw a lewis structure of the following compound: CO<sub>2</sub> [O=C=O with double bonds between C and each O] Carbon forms 0 single bonds and has 2 double bonds. Oxygen has 2 lone pairs. ## 11. The following questions refer to the Lewis Structure for C<sub>3</sub>H<sub>3</sub>N as shown in the figure above. [H-C=C-C≡N with a double bond between the first two carbons and a triple bond between the last two carbons] - a.) How many electrons are in the bond between carbon and nitrogen? 6 - b.) How many electrons are in the bond between the two carbons as indicated by the arrow? 4 - c.) How many nonbonding electrons (aka lone pairs) are in this structure? 1 lone pair, 2 electrons ## 12. The formula for vanadium (V) oxide is: V<sub>2</sub>O<sub>5</sub> ## 13. The formula for vanadium (III) oxide is: V<sub>2</sub>O<sub>3</sub> ## 14. You find a compound containing an unknown element. Its formula is: XF<sub>2</sub>. Which element can NOT be the identity of X? - a. Magnesium - b. Gallium - c. Calcium - d. Chromium ## 15. A stable, neutral compound contains two atoms of Nickel (III). Which of the following will balance the charge of this cation? - a. Two sulfide ions - b. One aluminum ion - c. Three oxide ions - d. Two fluoride ions ## 16. Match the following formulas with the compound names below. Be careful - some are ionic and some are covalent! - CuF<sub>2</sub>: C. Copper (II) Fluoride - IBr: D. Iodine Monobromide - Na<sub>3</sub>P: B. Trisodium Phosphide - Se<sub>2</sub>S<sub>6</sub>: A. Selenium Sulfide ## 17. Ionic compounds consist of metals bound to nonmetals. Covalent compounds consist of nonmetals bound to nonmetals. ## 18. When ionic bonds form, electrons are transferred. When covalent bonds form, electrons are shared. ## 19. Draw a lewis structure of the following compound: SiF<sub>4</sub> [F-Si-F with single bonds between Si and each F. Each F and Si has two lone pairs.] In order for the central silicon to have a full octet, it must make 4 bonds. Name the compound: Silicon tetrafluoride ## 20. Name the following compound: C<sub>6</sub>H<sub>10</sub> Hexacarbon decahydride ## 21. The formula for scandium selenide is: Sc<sub>2</sub>Se<sub>3</sub> ## 22. Consider the ionic compound formed from calcium (Ca) and phosphorus (P). Draw in the valence shell electrons in the diagram for calcium and for phosphorus: [Diagram of Ca with 2 dots representing valence electrons and P with 5 dots representing valence electrons] Which element is the electron donor? Ca Which is the electron acceptor? P How many electrons does each atom of Ca donate? 2 How many electrons does each atom of P accept? 3 How many atoms of calcium and phosphorus must be present in the compound's formula? 3Ca & 2P Identify the formula for the ionic compound formed from calcium and phosphorus. Ca<sub>3</sub>P<sub>2</sub> Correctly name this compound: Calcium phosphide ## 23. Consider the ionic compound formed from aluminum (Al) and nitrogen (N). Draw in the valence shell electrons in the diagram for aluminium and for nitrogen: [Diagram of Al with 3 dots representing valence electrons and N with 5 dots representing valence electrons] Which element is the electron donor? Al Which is the electron acceptor? N How many electrons does each atom of Al donate? 3 How many electrons does each atom of N accept? 3 How many atoms of aluminium and nitrogen must be present in the compound's formula? 1Al & 1N Identify the formula for the ionic compound formed from aluminium and nitrogen. AlN Correctly name this compound: Aluminium Nitride
