1. Start up 11/5/07 For each group indicate the number of valence electrons group 1Group 15 group 2Group 16 group 13Group 17 group 14Group 18 List the contributions of the following scientists: 1.Dalton 2.Rutherford 3.Bohr 4.Mendeleev

2. Start up 11/13/07 Copy the questions and the correct answer. 1.A student massed a piece of iron on a balance. The most sensitive beam was marked off in 0.1 g intervals. The student reported the iron’s mass as 12.34 g. Which of the digits in the measurement is estimated? A) 1B) 2C) 3D) 4 2.A student measured the temperature of a boiling solution and found it to be 56.0 °C at standard pressure. The theoretical temperature of that boiling solution is 55.0 °C. What is the percent error in the student’s measurement? A) 18 %B) 1.8 %C) 0.18 %D) 0.018 %

3. Ionic Bonds

4. chemical bond – the force that holds two atoms together. When positive ions form, an atom loses one or more electrons. The reason that an atoms form ions is to acquire noble gas configuration(8 valence electrons). Octet Rule – atoms tend to gain, lose or share electrons in order to have a “full” (8 electrons) outer energy level. Na – 1 valence e- Na +1 – 8 valence e-

5. Metals tend to lose electrons and become positive ions (cations). When a negative ion forms an atom gains one or more electrons F – 7 valence e- F -1 – 8 valence e- Nonmetals tend to gain electrons and become negative ions (anions). An outer energy level is considered “full” and therefore stable, if it has 8 electrons, except for the first energy level, only needs 2 electrons to be “full”

6. Common Ionic Charges (oxidation numbers) H Be BCNOF +1 +2+3-3-2 Multiple oxidation states (often +2) Group 14 elements have a tendency to form covalent bonds, not ionic, but when they form ionic bonds they usually form +4 or -4 ions.

7. Ionic bond – chemical bond resulting from the transfer of electrons from one atom to another Na – 1 valence e- F – 7 valence e- Na +1 – 8 valence e- F -1 – 8 valence e- Na + F - ionic bond forms

8. 11/7/07 Copy question and all answers 1.Which of the following pieces of glassware can be used to measure the volume of a liquid with the greatest accuracy? A) test tubeC) beaker B) flaskD) graduated cylinder 2.How many significant figures and in the measurement 20.0m? A) 1C) 2 B) 3D) 0

9. Na gives up its one valence electron to become Na + ; F gains the electron from Na to become F -. Opposite charges attract each other. Na : F : :.. Monatomic ions – ions formed from one atom. ex. Na +, Ca +2, Br -, Al +3 The charges for monatomic ions can be determined from the periodic table. Polyatomic ions – ions that consist of more than one atom. ex. NH 4 + - ammonium OH - - hydroxide CO 3 -2 - carbonate

10. Writing Chemical Formulas for Ionic Compounds Binary ionic compound – contains the ions of only two elements. calcium fluoride Ca +2 F -1 Compounds are neutral. How many -1 charges are required to neutralize one +2 charge? one calcium ion (+2) is neutralized by two fluorine ions (-1) (-1) Ca 1 F 2 CaF 2

11. magnesium oxide Mg +2 O -2 How many oxide ion -2 are needed to neutralize one magnesium ion +2. MgO

12. Criss-Cross Method of Writing Chemical Formulas Ca +2 F -1 The superscript (charge) of the cation, becomes the subscript for the anion and the superscript of the anion becomes the subscript for the cation. Ca 1 F 2 CaF 2

13. Mg +2 O -2 Mg 2 O 2 Ionic compounds are always reduced to the smallest whole number ratios. MgO calcium nitrate Ca +2 NO 3 -1 Ca (NO 3 ) 2 parentheses are used if you have more than one polyatomic ion.

14. Aluminum sulfate Al +3 SO 4 -2 Al 2 (SO 4 ) 3 Write chemical formulas for 1.potassium nitride 2.aluminum sulfide 3.calcium nitrate 4.calcium sulfate

15. Oxidation numbers for many monatomic ions are determined by the group of the periodic table. For some of the transition elements, there is more than one common oxidation state. For these metals the oxidation state of the ion is indicated in the name of the compound. Copper (I) chloride Copper (II) chloride CuClCuCl 2 Cu +1 Cl -1 Cu +2 Cl -1

16. Naming Chemical Compounds Given the chemical formula for a compound to name the compound, you simply name the positive ion and name the negative ion. NaCl Sodium chloride K 2 SO 4 Potassium sulfate Zn(NO 3 ) 2 Zinc nitrate If the cation has more than one oxidation number (ex. Fe +3 and Fe +2 ) this must be indicated in the name. Fe 2 O 3 Iron (III) oxide FeOIron (II) oxide For cations that form more than one ion, look at your ion chart.

17. 1.Potassium iodide 2.Barium chloride 3.Lithium bromide 4.Sodium hypochlorite 5.Iron(III) sulfate 6.Chromium sulfide 7.Calcium carbonate KI BaCl 2 LiBr NaClO Fe 2 (SO 4 ) 3 Cr 2 S 3 CaCO 3

18. 8. Sodium acetate 9. cobalt(II) fluoride 10. Sodium phosphide 11. Tin (IV) oxide 12. gold(III) bromide 13. copper(II) iodide 14. Strontium chloride NaC 2 H 3 O 2 CoF 2 Na 3 P SnO 2 AuBr 3 CuI 2 SrCl 2

19. 15. Lithium acetate 16. Magnesium hydroxide 17. Nickel (II) nitrate 18. Silver oxide 19. Zinc chloride 20. Magnesium phosphate LiC 2 H 3 O 2 Mg(OH) 2 Ni(NO 3 ) 2 Ag 2 O ZnCl 2 Mg 3 (PO 4 ) 2

20. Properties of Ionic Compounds 1.high melting points and boiling points. 2.Brittle, rigid solids at room temperature 3.Dissolve in water and become good conductors of electricity. 4.With the exception of ammonium, ionic compounds form between a metal and a nonmetal or a group of nonmetals.

21. Start up 11/12/07 Write formulas for the following compounds: 1.barium phosphate 2.Chromium (III) sulfate 3.potassium nitride 4.iron (III) chloride