Name ……………………………………………………………………………………
1.	Limestone contains the ionic compound, CaCO3. Limestone decomposes when it is heated strongly, forming an ionic compound, CaO and a covalent compound, CO2.
		CaCO3(s) ® CaO(s) + CO2(g)
(a)	State what is meant by ionic bonding.
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[1]
 
(b)	Draw ‘dot and cross’ diagrams to show the bonding in CaO and CO2. Show outer electron shells only.

	
CaO	CO2	
[3]
 
(c)	Complete the electronic configuration in terms of sub-shells for calcium in CaO.
1s2 ....................................................................................................................
[1]
[Total 5 marks]

2.	This question is about different models of bonding and molecular shapes.
	Magnesium sulfide shows ionic bonding.
(i)	What is meant by the term ionic bonding?
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[1]
 
(ii)	Draw a ‘dot-and-cross’ diagram to show the bonding in magnesium sulfide. Show outer electron shells only.

[2]
[Total 3 marks]
 3.	Magnesium fluoride, MgF2, has ionic bonding.
(i)	How does ionic bonding hold particles in MgF2 together?
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[2]
 (ii)	Draw a 'dot-and-cross’ diagram for magnesium fluoride, MgF2. Show outer electron shells only.

[2]

(iii)	Magnesium fluoride is produced when magnesium reacts with fluorine.
	Complete the half-equations below to show the formation of the ions in magnesium fluoride in this reaction.
Mg	®	....................	+	....................
F2	+	....................	®	....................
[2]
 (iv)	A student found that magnesium fluoride has different electrical conductivities when solid and when dissolved in water.
Explain these two observations.
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[2]
[Total 8 marks]
 
4.	Sodium reacts with oxygen to form sodium oxide, Na2O, which is an ionic compound.
(i)	Write the equation for the reaction of sodium with oxygen to form sodium oxide.
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[1]
 (ii)	State what is meant by the term ionic bond.
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[1]
(iii)	Draw a ‘dot-and-cross’ diagram to show the bonding in Na2O.
	Show outer electrons only.

[2]

Total: 20 marks

[Total 4 marks]