Download 1. Chlorine will combine with the non

1.
Chlorine will combine with the non-metal element, carbon, to form this molecular compound.
Cl
Cl
C
Cl
Cl
(a)
What is the type of bond in this molecule?
.....................................................................................................................................
(1)
(b)
Explain how these bonds are formed. (You may use a diagram).
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 3 marks)
Ashlyns School
1
2.
The questions which follow refer to the element hydrogen.
(a)
Draw a diagram to show the bonding in one molecule of hydrogen.
(2)
Ashlyns School
2
(b)
The table gives information about two compounds which contain hydrogen.
NAME
FORMULA
STRUCTURE
dilute
sulphuric
acid
H 2 SO 4
[H] + [SO 4 ]2– [H] +
H
H
×
C
C2H 4
ethene
×
C
×
×
H
H
Use the information in the table to explain why it is difficult to classify hydrogen as a
metal or a non metal.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 6 marks)
3.
Atoms of calcium, phosphorus and fluorine are represented below, each with its mass
number and proton number.
40
31
Ca
20
Ashlyns School
19
P
15
mass numbers
F
9
proton numbers
3
(a)
Use this information to complete the table.
CALCIUM
Number of protons in the nucleus
20
Number of neutrons in the nucleus
20
Number of electrons
PHOSPHORUS
FLUORINE
9
16
15
9
(3)
(b)
Calcium and fluorine atoms can combine to form the compound calcium fluoride, CaF2.
The fluoride ion is represented by F–.
(i)
Explain how the fluorine atom forms a fluoride ion.
..........................................................................................................................
..........................................................................................................................
(2)
(ii)
How is the calcium ion represented?
..........................................................................................................................
(2)
(c)
Phosphorus and fluorine form a covalent compound, phosphorus trifluoride.
Complete the sentences below which are about this compound.
Phosphorus trifluoride is made up of phosphorus and fluorine ................................
These are joined together by sharing pairs of ............................................... to form
phosphorus trifluoride ........................................................ .
(3)
Ashlyns School
4
(d)
(i)
Sodium chloride, an ionic compound, has a high melting point whereas paraffin
wax, a molecular compound, melts easily.
Explain why.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(ii)
Molten ionic compounds conduct electricity but molecular compounds are
non-conductors, even when liquid.
Explain why.
..........................................................................................................................
..........................................................................................................................
..........................................................................................................................
(2)
(Total 14 marks)
4.
(a)
The diagrams represent the atomic structures of two gases, hydrogen and helium.
x = an electron
p = a proton
n = a neutron
2p
2n
hydrogen
helium
Hydrogen gas is made up of diatomic molecules (molecules with two atoms).
Helium gas exists as single atoms.
Ashlyns School
5
(i)
How is a molecule of hydrogen formed from two hydrogen atoms?
(You may use a diagram as part of your answer)
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(ii)
Why does helium exist only as single atoms?
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(b)
Hydrogen combines with carbon to form methane.
Each molecule contains four hydrogen atoms strongly bonded to a carbon atom.
methane molecules
H
H
H
H
H
C
H
C
H
H
H
H
H
H
C
H
H
H
H
H
H
H
structural formula
of methane CH 4
C
H
H
C
H
H
H
Explain why methane has a low boiling point.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 6 marks)
Ashlyns School
6
5.
(a)
Ammonium nitrate and ammonium sulphate are used as fertilisers.
(i)
Which acid reacts with ammonia to form ammonium nitrate?
...........................................................................................................................
(1)
(ii)
Which acid reacts with ammonia to form ammonium sulphate?
...........................................................................................................................
(1)
(iii)
The reactions in (i) and (ii) are both exothermic. How can you tell that a reaction is
exothermic?
...........................................................................................................................
...........................................................................................................................
(1)
Ashlyns School
7
(iv)
The reactions in (i) and (ii) are both examples of acid + base reactions. What is the
name of the chemical change which takes place in every acid + base reaction?
...........................................................................................................................
(1)
(b)
On a bag of fertiliser it claims that it will make plants grow well. State one way in which
plants which grow well are different from plants which do not grow well.
....................................................................................................................................
....................................................................................................................................
(1)
(c)
The chemical formula for ammonia is NH3. Complete the four spaces in the passage.
One atom of ....................................... and three atoms of ........................................
form one .................................... of ammonia. Ammonia is a covalent compound so
these atoms are joined by covalent bonds formed by sharing ................................. .
(4)
(d)
Covalent substances which are not giant structures have low melting points and low
boiling points. They are liquids or gases at room temperature and often have a distinct
smell.
Give one other property which they share.
....................................................................................................................................
....................................................................................................................................
(1)
(Total 10 marks)
Ashlyns School
8
6.
The diagram shows the giant structure of sodium chloride.
Sodium chloride (melting point 801 °C)
By reference to the structure of sodium chloride, explain fully why:
(a)
sodium chloride has quite a high melting point;
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(1)
(b)
solid sodium chloride melts when it is heated strongly;
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
Ashlyns School
9
(c)
molten sodium chloride will conduct electricity.
.....................................................................................................................................
.....................................................................................................................................
(1)
(Total 4 marks)
7.
(a)
The table contains some information about two elements.
Number of
(i)
Element
Symbol
protons
neutrons
electrons
fluorine
F
9
10
9
chlorine
Cl
17
18
17
chlorine
Cl
17
20
17
In terms of atomic structure, give one feature that both these elements have in
common.
...........................................................................................................................
(1)
(ii)
There are two isotopes of chlorine shown in the table. Explain what isotope means.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
Ashlyns School
10
(iii)
Explain, in terms of electron arrangement, why fluorine is more reactive than
chlorine.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(b)
Sodium reacts with chlorine to form the compound sodium chloride.
2Na + Cl2  2NaCl
Describe, in terms of electron arrangement, the type of bonding in:
(i)
a molecule of chlorine;
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
Ashlyns School
11
(ii)
the compound sodium chloride.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(4)
(Total 12 marks)
8.
The transition elements have the typical properties of metals.
(i)
Transition metals are good conductors of electricity.
Explain why.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(ii)
Transition metals have high melting points.
Explain why.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 4 marks)
Ashlyns School
12