Set 2
Marking Scheme :Periodic Table of Elements & Chemical Bonds
2010
PERIODIC TABLE OF ELEMENTS
PAPER 2 – STRUCTURE
No.
1
Rubric
(a) (i)
(ii)
(b) (i)
(ii)
(c) (i)
Marks
Group 1
1
Period 3
1
F
1
E2L
1
Soluble in water// high melting point/ boiling point// conducts
electricity in molten or aqueous solution
1
E
1
The nuclei attraction towards the valence electron is weaker in E.
1
(ii)
Thus it is easier for E to lose/ release an electron to form a
(d) (i)
(ii)
positively charged ion.
1
A//C
1
Covalent bond
1
Total marks
No.
2
Explanation
10
Marks
(a) (i)
T
1
(ii)
Q
1
(iii)
S
1
(b)
Q, P, T, S and R
1
(c)
2.8.3
1
(d)
T-
1
(e)
Both have the same number of shells of electrons
1
(f)
Red litmus paper turns blue
1
(g)
Transition elements
1
Total marks
Chemistry Perfect Score Module Form 4 2010 Marking Scheme Set 2
9
10
Set 2
Marking Scheme :Periodic Table of Elements & Chemical Bonds
No.
3
Explanation
2010
Marks
(a) (i)
D+
1
(ii)
B2-
1
(b) (i)
18
1
2.8.8
1
(c)
G
1
(d) (i)
DE
(ii)
1
r: ED, chemical equation
(ii)
+
-
Ion D+
-
-
Ion E-
1. [All electrons and number of shells filled with electron
1
correct]
2. [Nucleus of atom labeled and charges of ion shown
1
correctly]
(iii)
In aqueous solution//molten state
1
Ions can move freely//free to move
1
Total marks
10
PAPER 2 - ESEI
No.
4
(a) (i)
(ii)
Explanation
Marks
Electron arrangement: 2.8.7
1
Element: Chlorine
1
2NaOH + Cl2
NaCl + NaOCl + H2O
Correct reactant
1
Correct product
1
Balanced equation
1
(b)
1
The valence shell of electrons in diagram 4.1 is nearer to the
nucleus compared to diagram 4.2
Chemistry Perfect Score Module Form 4 2010 Marking Scheme Set 2
11
Set 2
Marking Scheme :Periodic Table of Elements & Chemical Bonds
Diagram 4.2 has 3 shells and diagram 4. 1has 2 shells.
2010
1
The nuclei attraction in diagram 4.1 is stronger than diagram 4.2.
Diagram 4.1 is more electronegative than diagram 4.2 because it is
1
easier to receive electron.
Diagram 4.1 is more electronegative and more reactive than
1+1
diagram 4.2. //
(c)
(d) (i)
(ii)
Atomic size /
distance between
nucleus and
valence electrons.
Nuclei
attraction
between
nucleus
and
valence
electrons
Tendency
to
receive electrons to
form negative ion
Reactivity
Less reactive
Atom diagram 4.1
Smaller / nearer
Atom diagram 4.2
Bigger / farther
Stronger
Weaker
Easier
Difficult
More
Less
1
1. all connection of the apparatus are tight to avoid the leakage og
gas.
2. carry out the experiment in fume chamber.
3. pour the hydrochloric acid carefully to avoid it from spilling.
In Part A;
Iron wool reacts with chlorine gas to form solid iron (III) chloride.
3Cl2 + 2Fe
2FeCl3
In Part H;
Sodium chloride, sodium chlorate (I) and water are formed from
the reaction between excess chlorine and sodium hydroxide
solution.
2NaOH + Cl2
NaCl + NaOCl + H2O
Total marks
Chemistry Perfect Score Module Form 4 2010 Marking Scheme Set 2
1
1
1
1
1+1
1
1+1
20
12
Set 2
Marking Scheme :Periodic Table of Elements & Chemical Bonds
2010
PAPER 3 - STRUCTURE
No.
Explanation
Marks
5(a) To state the variables
Explanation
No.
Explanation
Manipulated variable : metals of
Group 1 elements // sodium,
lithium, potassium.
Repeat the experiment by using the
metals of sodium, lithium and
potassium
Responding variable: the
reactivity of the reaction with
water // the speed of movement
on the water surface
To observe how fast the metals move
on the surface of water.
Constant variable: size/mass of
metals. Volume of water
Use the metal granules with the same
size.
Explanation
[Able to state the relationship between the manipulated variable and the
responding variable correctly]
The reactivity of Group 1 elements increases going down the group.
No.
(c)
No.
(d)
No.
(e)
Explanation
[Able to arrange correctly the reactivity series of the metals according to
descending order]
potassium, sodium, lithium
Explanation
The metal that reacts more vigorously with water is a more reactive metal.
Explanation
[Able to classify the ions correctly]
6
Marks
3
Marks
3
Marks
3
Marks
3
Positive ion/ cation : sodium ion/ Na+, hydrogen ion/ H+
Negative ion/anion : hydroxide ion/ OH-
Chemistry Perfect Score Module Form 4 2010 Marking Scheme Set 2
13
Set 2
Marking Scheme :Periodic Table of Elements & Chemical Bonds
2010
PAPER 3 - ESEI
No.
6(a)
Explanation
[ Able to state the problem statement clearly and accurately]
How does the reactivity of Group 1 elements change when they react with
water?
[Able to state the problem statement slightly inaccurate]
To study the reactivity of Group 1 elements.
3
[Able to provide an idea of a problem statement]
The reactivity of Group 1 elements.
No response given / wrong response
1
No.
(b)
Explanation
(c)
2
0
Marks
Stating variables
[Able to state all the corresponding variables accurately]
Manipulated variable
: Type of Group 1 metals
Responding variable
: Reactivity of reaction
Fixed variables
: Water, size of metals
No.
Marks
3
[Able to state two corresponding variables accurately]
2
[Able to state any one corresponding variable correctly]
1
No response given / wrong response
0
Explanation
Marks
[Able to list all materials and apparatus correctly]
Materials
A small piece of lithium, sodium, potassium and water
Apparatus
[Suitable container], forceps, Knife, filter paper
3
[Able to list the basic materials and apparatus required]
A small piece of lithium, sodium and potassium, water
Apparatus
[Suitable container], forceps
2
[Able to provide an idea of materials and apparatus used]
Group 1 metals, water, forceps
No response given / wrong response
1
Chemistry Perfect Score Module Form 4 2010 Marking Scheme Set 2
0
14
Set 2
Marking Scheme :Periodic Table of Elements & Chemical Bonds
No.
Explanation
2010
Marks
[Able to state all experimental steps correctly]
1. Cut a small piece of lithium using a knife and forceps.
2. Dry the oil on the surface of the lithium with filter paper.
3. Place the lithium slowly onto the water surface in a trough
4. Observe the reactivity of the reaction
5. Repeat steps 1 to 4 using sodium and potassium to replace
lithium
3
[Able to provide 3 steps correctly to carry out the experiment]
Steps 3,4 and 5
2
[Able to provide minimum of 2 steps correctly to carry out the
experiment]
Steps 3 and 4
No response given / wrong response
1
No.
Explanation
[Able to construct a table correctly containing the following
elements]
Metals
0
Marks
3
Observations
Lithium
Sodium
Potassium
[Able to construct a tabulation of data containing the following
elements]
Metals
2
Observation
[An idea of a tabulation of data ]
- Minimum of 2 rows and columns
1
No response given / wrong response
0
Chemistry Perfect Score Module Form 4 2010 Marking Scheme Set 2
15