Chapter 5: Ions & Ionic Compounds Study Guide

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1 Name: Date: Chapter 5: Ions & Ionic Compounds Study Guide Directions: Work to answer the following review questions. You may use your notes and textbook as a reference. Answers to the review sheet will be posted to Edline and School Wires at the end of the day. It will be your responsibility to check your answers and ask questions prior to the test on Friday, January 30, Study guides will be collected during the test and you will receive a grade for having them completed. 1. What is an ion? An ion is an atom or group of atoms with a positive or negative charge. 2. What are the names given to positively charged ions and negatively charged ions, respectively? cation (+) & anion (-) 3. Compounds that have the same number of positive and negative charges are said to be electrically neutral. 4. Explain the octet rule. Atoms will react by either gaining or losing electrons in order to have 8 valence electrons similar to the stable noble gases (Exception: Hydrogen only has 2 v.e.) 5. Why do atoms of metals tend to form cations? Metals tend to have few valence electrons (Group 1-1 v.e, Group 2 2 v.e., etc). It requires less energy for metals to lose those few valence electrons than to gain enough to have a noble gas configuration. If atoms lose electrons, they become positively charged making them cations.

2 6. Why do atoms of nonmetals tend to form anions? Nonmetals tend to have more valence electrons (Group 15 5 v.e, Group 16-6 v.e., Group 17-7 v.e., etc). It requires less energy for nonmetals to gain the few valence electrons that they need rather than losing enough to have a noble gas configuration. If atoms gain electrons, they become negatively charged making them anions. 7. A calcium ion has a configuration similar to which noble gas? Is this ion a cation or anion? Why? Calcium will lose two electrons giving it a configuration similar to Argon. Calcium lost electrons; therefore, it becomes positively charged making it a cation. 8. A iodine ion has a configuration similar to which noble gas? Is this ion a cation or anion? Why? Iodine will gain one electron giving it a configuration similar to Xenon. Iodine gained an electron; therefore, it becomes negatively charged making it an anion. 9. Explain why the properties of ions differ from those of their parent atoms. Properties of ions differ from those of their parent atoms because they contain a different number of electrons. 10. Explain how ions differ from the noble gases that they share an electron configuration with. Ions differ from the noble gases that they share an electron configuration with because they contain different numbers of protons. 11. How many valence electrons does the element with the electron configuration 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 have? 4- Highest energy level 1 electron in highest energy level = 1 valence electron

3 12. How can an element with the electron configuration 1s 2 2s 2 2p 5 have an octet? 7 valence electrons Gain 1 electron 13. How can an element with the electron configuration 1s 2 2s 2 2p 6 3s 2 have an octet? 2 valence electrons Lose 2 electrons 14. Which of the following electron configurations belong to an element that is the most chemically reactive? a. 1s 2 Helium (stable) b. 1s 2 2s 2 2p 6 Neon (stable) c. 1s 2 2s 2 2p 5 Fluorine (not stable) d. 1s 2 2s 2 2p 6 3s 2 3p 6 Argon (stable) 15. The formula unit is the simplest repeating unit of a crystal structure. 16. Name 3 characteristics of ionic compounds. High melting point Conduct electricity when melted or dissolved in water Crystalline structure Typically solids at room temperature 17. When are salts excellent conductors of electricity? Explain. Salts are excellent conductors of electricity when they are melted or dissolved in water. Salts have a rigid crystalline structure that does not allow the ions to move freely. When the salt is melted or dissolved in water, the ions are able to move about freely and conduct electricity.

4 18. What is a polyatomic ion? Give 3 examples. A polyatomic ion is a tightly bound group of atoms that behaves as a unit and has a positive or negative charge. 24. Write the names of the following. Use roman numerals if needed. a) Cu + copper (I) ion b) Cl - chloride ion c) O 2- oxide ion d) P 3- phosphide ion e) Na + sodium ion f) Mg 2+ magnesium ion g) NaCl sodium chloride h) ZnS zinc sulfide i) Fe2O3 iron (III) oxide j) NaI sodium iodide k) Cu2O copper (I) oxide l) CaCl2 calcium chloride 25. Write the formulas for the following. a) lead (IV) chromate Pb (CrO4)2 b) sodium hypochlorite NaClO c) barium fluoride BaF2 d) tin (IV) oxide SnO2 e) potassium bromide KBr f) mercury (I) sulfide Hg2S g) sodium peroxide Na2O2 h) hydrogen cyanide HCN i) ammonium sulfate (NH4)2 SO4

5 j) magnesium nitrate Mg (NO3)2 k) sodium chloride NaCl l) aluminum hydroxide Al (OH)3