11 Chem Chapter 8 Ionic Bonding 2

11 Chem Chapter 8 Ionic Bonding 1

1. How many valence electrons does each of the following atoms have? a. Potassium b. carbon c. magnesium d. oxygen 1 4 2 6 2. State how many electrons will be gained or lost for the following elements in forming an ion a. calcium b. fluorine c. aluminum d. oxygen loss of 2 gain one loss of 3 gain 2 3. Write the formula for the ion when the element becomes isoelectronic with a Noble gas. a. sulphur b. sodium c. fluorine d. barium S-2 Na+1 F-1 Ba+2 4. Use electron dot symbols (Lewis structure) to determine the formula unit and then name the ionic compounds formed when the following elements combine. a. potassium and iodine · ·· K · F : K+1 F-1 KF potassium fluoride ·· +2 -1 b. calcium and chlorine Ca Cl CaCl2 calcium chloride +3 -2 c. aluminum and sulfur Al S Al2S3 aluminum sulfide +2 -3 d. magnesium and phosphorus Mg P Mg3P2 magnesium phosphide 5. Define the term valence electrons. Valence electrons - electrons in the highest number energy level consisting of s and p sublevels. 6. Write the electron dot structures for each of the following elements. a. S b. C c. Al d. Be e. Cl ·· · · · ·· · O : ·C· Al· Be· ·Cl: · · · ·· 7. The atoms of the noble gas elements are stable. Explain. Noble gasses all have a complete valence shell which is the most stable electron configuration. 8. Write the complete electron configuration for the following atoms and ions. Comment on the results: Ar, K+, Ca2+ Ar 1s22s22p63s23p6 K+ 1s22s22p63s23p6 Ca2+ 1s22s22p63s23p6 All have the same full shells. Isoelectronic. 9. What are cations and anions? How and why are cations and anions produced? Cations are + ions formed when atoms lose electrons. Anions are – ions formed when atoms gain electrons. The ions form so the element can attain a full shell configuration – isoelectronic with a noble gas. 10. Why are ionic compounds electrically neutral? The number of electrons lost = the number of electrons gained so the + cancels out the -. 11. Write the correct chemical formula for the compound formed by the following pairs of ions: a. Na+ and F- b. K+ and S2- c. Ca2+ and N3- d. Al3+ and O2- NaF K2S Ca3N2 Al2O3 11 Chem Chapter 8 Ionic Bonding 2

12. Which of the following pairs of elements are most likely to form ionic compounds? a. chlorine and bromine b. potassium and helium c. lithium and fluorine d. iodine and sodium C and D because they are a metal – nonmetal pair. 13. Write the formula for the ions in the following compounds. a. LiF b. BaO c. Na2S d. Al2O3 e. Ca3N2. +1 -1 +2 -2 +1 -2 +3 -2 +2 -3 a. Li F b. Ba O c. Na S d. Al O e. Ca N . 14. In your own words describe a crystal. A crystal is a regular repeating pattern of cations and anions leading to closest packing to neutralize charges. 15. Most ionic compounds are brittle. Why? They are brittle because the forces of attraction between the cation and anion are very strong and if the ions are shifted the + will repel + and the – repel – and the crystal will shatter.

16. Why does molten MgCl2 conduct an electric current although crystalline MgCl2 does not? How else can we get MgCl2 to conduct a current? To conduct an electric current there must be mobile charges present. Molten or melted MgCl2 has ions in the liquid state so the ions (charges) can move. Another way to make the ions mobile is to dissolve the MgCl2 in water. 17. In your own words define a metallic bond. Metals hold onto their valence electrons very weakly. Valence electrons are free to move through the solid. Metals can be described as a group of cations tightly packed together and are surrounded by valence electrons, which are in continuous motion around the cations. It is therefore very hard to determine which electron belongs to which cation. This attraction of “free- floating” valence electrons around the cation is called a metallic bond. 18. Describe what is meant by the terms ductile, and malleable. Explain why metals exhibit these properties. The valence electron cloud isolates the cations from one another as they “roll” around in the structure. This ensures a great mobility for the cations as well. So, it is possible to make the cations slide on top of one another so that we can change the shape of their structure without affecting the composition of the metal.. Metals are malleable that is they can be hammered into different shapes (can be bent). Metals are ductile that is they can be drawn into wires (valence electrons allow atoms to slide by each other) 19. Explain why it is possible to bend metals but not ionic crystals? Metal atoms are held together in the solid as positive ions floating in a sea of electrons. The loosely held valence electron cloud allows the metals atoms (cations) to move over each other – can change shape. Ionic solids can not change shape because the forces of attraction between the cation and anion are very strong, if the ions are shifted the + will repel + and the – repel – and the crystal will shatter. 20. Explain why metals are good conductors of electricity. Metal atoms are held together in the solid as positive ions floating in a sea of electrons. The loosely held valence electron cloud allows for the flow of charge. Thus metals are conductors of electricity. 11 Chem Chapter 8 Ionic Bonding 3 Nomenclature Name the following binary ionic compounds: 1) MgS __ magnesium sulfide ___ 2) KBr __ potassium bromide ______

3) Ba3N2 __ barium nitride ___

4) Al2O3 __ aluminum oxide __ 5) NaI ___ sodium iodide ______

6) SrF2 ___ strontium fluoride ___

7) Li2S ___ lithium sulfide _____ 8) CaO ____ calcium oxide _____

9) K2S ____ potassium sulfide ___ 10) LiBr ____ lithium bromide _____ Write a formula for the binary ionic compounds: 1) magnesium oxide _____ MgO ______2) lithium bromide _____ LiBr ______

3) calcium nitride _____ Ca3N2______

4) aluminum sulfide _____ Al2S3______5) potassium iodide ______KI ______

6) strontium chloride _____ SrCl2______

7) sodium sulfide _____ Na2S ______

8) radium bromide ____ RaBr2______9) magnesium sulfide _____ MgS ______10) aluminum nitride _____ AlN ______Name for the following, use the Stock system. 1) CuS ______copper(II) sulfide ____

2) Fe2O3 ____ iron(III) oxide ___

3) FeI2 _____ iron(II) iodide ______

4) Cu2S ______copper(I) sulfide ______

5) SnCl2 ______tin(II) chloride ______6) CuO _____ copper(II) oxide ____

7) PbF2 _____ lead(II) fluoride ______

8) CuCl2 ____ copper(II) chloride ______9) CuBr _____ copper(I) bromide ______11 Chem Chapter 8 Ionic Bonding 4 10) PbO ______lead(II) oxide ______Use the Stock system to write the formula for:

1) iron(II) chloride ____ FeCl2____

2) copper(I) sulfide ____ Cu2S ______

3) lead(IV) iodide ___ PbI4____

4) tin(II) fluoride _____ SnF2___

5) chromium(III) oxide __ Cr2O3 _____

6) iron(II) nitride ____ Fe3N2___ 7) cobalt(III) phosphide _ CoP ___

8) iron(III) chloride _____ FeCl3__ 9) copper(II) sulfide __ CuS ____

10) lead(II) bromide ____ PbBr2_____ Ternary Compounds Write the correct chemical name for:

1) AlPO4 __ aluminum phosphate ___

2) CaCO3 __ calcium carbonate __

3) Mg(OH)2 ___ magnesium hydroxide __

4) K2SO4 __ potassium sulfate __

5) Na2CO3 __ sodium carbonate __

6) NH4NO3 __ ammonium nitrate __

7) Sn(NO3)2 ____ tin(II) nitrate __

8) FePO4 _ iron(III) phosphate ____

9) PbCO3 __ lead(II) carbonate __

10) Cu2CO3 ___ copper(I) carbonate __ Write the correct chemical formula for:

1) potassium phosphate __ K3PO4__

2) aluminium hydroxide __ Al(OH)3_

3) sodium hydrogen carbonate __ NaHCO3_

4) calcium nitrate _ Ca(NO3)2__

5) sodium carbonate _ Na2CO3_

6) tin(II) carbonate _ SnCO3___

7) lead(II) sulfate __) PbSO4_

8) iron(III) carbonate __ Fe2(CO3)3_ 11 Chem Chapter 8 Ionic Bonding 5 9) potassium hydroxide ____ KOH ___

10) ammonium sulfate _(NH4)2SO4_