Critical Thinking

26. Classifying What does a fluoride ion have in common with a neon atom and a sodium ion?

27. Comparing and Contrasting How are molecules and polyatomic ions similar?

28. Classifying Classify the bonds in each of these compounds as ionic, polar covalent, or nonpolar covalent: SO₃, CaO, and I₂.

29. Applying Concepts Write the names for the compounds with these chemical formulas: SCl₂, Ag₂SO₄, LiF, CS₂, and Ca(OH)₂.

Use these diagrams to answer Questions 30–34.

30. Using Models Which of the three elements are metals and which are nonmetals?

31. Applying Concepts Element Q forms compounds with element X and with element Z. Write the formulas for these two compounds.

32. Calculating What would the formula be for a compound containing chromium(III) ions and ions of element Z?

33. Applying Concepts Draw an electron dot structure for a compound of fluorine and Z.

34. Predicting If an atom of X reacts with an atom of X, what kind of bond forms?

Math Skills

35. Calculating What is the total number of shared electrons in a carbon dioxide molecule?

36. Making Generalizations What is the ratio of anions to cations in a compound formed by a Group 2A metal and a Group 7A nonmetal?

37. Applying Concepts Write the formulas for barium fluoride, sodium oxide, iron(II) sulfate, and ammonium sulfate.

Concepts In Action

38. Using Models A solution of hydrogen peroxide (H₂O₂) and water is sometimes used to disinfect a cut. Which of the following formulas is the correct structural formula for hydrogen peroxide?

    

39. Relating Cause and Effect In a carbonated beverage, the main ingredients are water and carbon dioxide. Carbon dioxide gas is released when the bottle is opened. Why is water a liquid but carbon dioxide a gas at room temperature?

40. Classifying The shells shown on page 156 contain the compound calcium carbonate (CaCO₃). Explain how this compound can contain both ionic and covalent bonds.

41. Relating Cause and Effect How does adding some phosphorus to silicon make silicon a better conductor of electric current?

42. Writing in Science Compare what happens to the valence electron in a hydrogen atom when the atom bonds with another hydrogen atom and when the atom bonds with an oxygen atom.

Performance-Based Assessment

Designing an Advertisement You own a store that sells bronze bells. Design a quarter-page ad for your store to be published in your local directory of businesses. Write copy for your ad. Describe a photograph to use in the ad. Also supply a sketch showing how you want the copy and the photograph to be laid out on the page.

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