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Unformatted text preview: shah (rps587) Homework 3 mcdevitt (52365) 1 This print-out should have 35 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points With respect to chemical bonding, which par- ticles play the most active role? 1. protons 2. valence electrons correct 3. neutrons 4. core electrons Explanation: 002 10.0 points Which of the following properties is generally NOT associated with ionic bonding? 1. crystalline solid 2. soluble in nonpolar solvents correct 3. All of the other choices are properties of ionically bonded substances. 4. high melting and boiling points 5. aqueous solutions conduct electricity Explanation: Opposites attract so atoms in ionic bonds are attracted to other atoms that are charged or partially charged. 003 10.0 points Which of the following is the best represen- tation of the compound calcium fluoride? 1. None is appropriate because calcium flu- oride is a covalent compound. 2. Ca 2+ , bracketleftbigg F b b b b b b b b bracketrightbigg 2- 3. 3 Ca 2+ , 2 bracketleftbigg F b b b b b b b b bracketrightbigg 3- 4. Ca + , bracketleftbigg F b b b b b b b b bracketrightbigg- 5. 2 Ca + , bracketleftbigg F b b b b b b b b bracketrightbigg 2- 6. Ca 2+ , 2 bracketleftbigg F b b b b b b b b bracketrightbigg- correct Explanation: The best drawing will show the valence electrons and the appropriate ratio of ions in CaF 2 , as well as charges on ions. 004 10.0 points Which of the following is the best description of ionic bonding? 1. bonding that occurs between elements with similar electronegativities, and with sharing of electrons 2. bonding that occurs between elements with very different electronegativities, and with sharing of electrons 3. bonding that occurs between elements with similar electronegativities, and with transfer of electrons 4. bonding that occurs between elements with very different electronegativities, and with transfer of electrons correct 5. bonding that occurs between ions and elements, and with the sharing of electrons Explanation: Ionic bonding occurs between metals and non-metals. Metals have low electronega- tivity values and non-metals generally have high electronegativity values. Ionic bonding involves the transfer of electrons, with the low electronegativity element losing electrons and the high electronegativity element gain- ing electrons. 005 10.0 points Predict the most common ion formed by bar- ium. shah (rps587) Homework 3 mcdevitt (52365) 2 1. Ba + 2. Ba 2+ correct 3. Ba- 4. Ba 3+ Explanation: A barium atom has the electron configura- tion [Xe] 6 s 2 . There are two valence electrons. In order to obtain a noble gas configuration (a filled outer energy level), Ba would lose its outer two electrons, leaving it with the same number of electrons as Xe. The resulting ion will have two fewer electrons than protons, so it will have a +2 charge....
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This note was uploaded on 04/16/2009 for the course CH 52365 taught by Professor Mcdevitt during the Spring '09 term at University of Texas at Austin.
- Spring '09