Name ……………………………………………………………………………………
1.	Chemists use the Periodic Table to predict the behaviour of elements.
	Early attempts at developing a Periodic Table arranged elements in order of increasing atomic mass.
(i)	State which two elements from the first twenty elements of the modern Periodic Table are not arranged in order of increasing atomic mass.
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[1]
 (ii)	Why does the modern Periodic Table not arrange some elements, such as those in (i), in order of increasing atomic mass?
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[Total 2 marks]
2.	The table below shows the melting points and atomic radii of the elements in Period 3, Na to Cl.

element	Na	Mg	Al	Si	P	S	Cl	
melting point / °C	98	639	660	1410	44	113	–101	
atomic radius / pm	186	160	143	118	110	102	99	
1pm = 1 x 10-12 m
(a)	(i)	Explain the difference in melting point for the elements Na and Mg.
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 (ii)	Sulfur exists as S8 molecules and chlorine as Cl2 molecules. Use this information to explain the difference in their melting points.
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(b)	Explain the decrease in the atomic radii across the period from Na to Cl.
	In your answer, you should use appropriate technical terms, spelt correctly.
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[Total 8 marks]
 3.	This question refers to the elements in the first four periods of the Periodic Table.

	Identify an element from the first four periods that fits each of the following descriptions.
(i)	The element that forms a 2– ion with the same electronic configuration as Ar.
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[1]
(ii)	The element that forms a 3+ ion with ten electrons.
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(iii)	An element that forms a compound with fluorine with trigonal planar molecules.
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(iv)	The element that forms a chloride XCl2 with a molar mass of 111.1 g mol–1.
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 (v)	The element with the largest atomic radius.
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(vi)	The element with the smallest first ionisation energy.
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[Total 6 marks]
 4.	The diagram below shows the variation in the boiling points of elements across
Period 3 of the Periodic Table.

(a)	In the table below for the elements Mg, Si and S,
•	complete the structure column using the word giant or simple.
•	complete the bonding column using the word metallic, ionic or covalent.
element	structure	bonding	
Mg			
Si			
S			
[3]
 
(b)	Explain why silicon has a much higher boiling point than phosphorus.
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(c)	Explain why the boiling point increases from sodium to aluminium.
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[Total 7 marks]