The Ion Card Game Purpose: To write correct formulas for ionic compounds. Introduction: Ions are charged atoms or groups of atoms (____________________ __________). They are found in compounds that consist of a _______________ combined with a ____________________. For example, sodium chloride (NaCl) is a compound containing sodium+1 ions and chlorine (called “chloride”)-1 ions. Just like oppositely charged magnets are attracted to each other, positive ions attract negative ions. When these oppositely charged ions combine together, they must form a ________________ compounds. That is when you add up the number of positive and negative charges present the total must always equal ___________________. The charge on an ion cannot be changed. It is characteristic of the ion. What you can do is to add subscripts indicating the number of each ion needed to make the total charge zero. For example, it takes two Cl- to balance one Mg+2 ion, so the formula for magnesium chloride is MgCl2. By convention, we always write the cation ion (____________) first and the anion (_________________) second in a chemical formula. In addition to monoatomic ions, some ions are composed of a group of two or more atoms with a combined net charge. These are called ____________________ ______________. For example, the nitrate ion (NO3-1) contains one nitrogen atom and three oxygen atoms with a combined charge of -1. Procedure 1. Cut out your ion pieces. 2. Make the following neutral ionic compounds by putting the given cards together and indicate the correct chemical formula. Combine one or more like positive ions with one or more like negative ions so that the sum of the charges equals zero. When the cards form a square or rectangle, the sum of the charges equals zero. NAME Formula NAME sodium chloride potassium iodide copper (II) bromide calcium sulfide iron (II) chloride potassium sulfide aluminum oxide copper (II) sulfide Formula 3. Make more neutral ionic compounds with the given cards and indicate the correct chemical formula. Don’t forget to use parentheses around the polyatomic ions when you need to show two or more of these charged groups in a formula. For example, ammonium oxide is (NH4)2O. NAME Formula NAME calcium sulfate silver phosphate iron (III) hydroxide magnesium phosphate calcium nitrite copper (I) carbonate hydrogen phosphate copper (II) cyanide sodium phosphate lithium carbonate iron (III) nitrate cesium sulfate rubidium acetate rubidium permanganate Formula Questions: 4. What is the charge of the iron ion in iron (II) chloride? ___________________________ 5. In the polyatomic ion NH4+1, How many atoms are there of nitrogen? _____________________________ How many atoms are there of hydrogen? ____________________________ What is the charge of this ion? ____________________________________ 6. What is the charge of the following? (Look on your Ion Sheet) the sulfate ion ______________________the oxalate ion _____________________ the dichromate ion ___________________the nitrite ion ______________________ 7. In the compound (NH4)3PO4, how many of each of the following atoms are there? N _____ H_____ P_____ O_____ 8. In the compound Ca3(AsO4)2, how many of each of the following atoms are there? Ca _____ As_____ O_____ 9. Mario was absent from school when you learned to write formulas for ionic compounds. In one or two clear sentences, please explain how to write a formula. 10. Using your rule from number nine, write the ionic formula for each of the following combining substances: Lithium and Chromate: ______________________________________ Calcium and Hydroxide: _____________________________________ Lead (II) and Fluoride: ______________________________________ 11. Using your ion sheet, create three new ionic compounds that do not contain any of the ions used thus far in this activity. List the combining substances, and write the formulas. Be sure to combine a positive ion with a negative ion and use subscripts to make the overall charge equal zero. Combining Substances Formula ____________________ and ____________________ ____________________ and ____________________ ____________________ and ____________________ 12. In ions like iron (III) and lead (II), what do you think the Roman numerals in parenthesis represent?
