11 Chem
Chapter 8 Ionic Bonding
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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
··
b. calcium and chlorine Ca+2 Cl-1 CaCl2 calcium chloride
c. aluminum and sulfur Al+3 S-2 Al2S3 aluminum sulfide
d. magnesium and phosphorus Mg+2 P-3 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.
··
·
·
·
·O:
·C·
Al·
Be·
·
·
·
Cl
··
·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 Fb. K+ and S2c. Ca2+ and N3d. Al3+ and O2NaF
K2S
Ca3N2
Al2O3
11 Chem
Chapter 8 Ionic Bonding
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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
a. Li+1 F-1
b. Ba+2 O-2
c. Na+1 S-2
d. Al+3 O-2
e. Ca3N2.
e. Ca+2 N-3 .
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 MgCl 2 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 “freefloating” 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
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 _______
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11 Chem
Chapter 8 Ionic Bonding
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_
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Chapter 8 Ionic Bonding
11 Chem
9) potassium hydroxide
____ KOH ___
10) ammonium sulfate
_(NH4)2SO4_
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