Table 1 shows the proton numbers of elements P, Q, and R. (1) P, Q, and R form ionic bonds when combined. PQ2 and R2Q have different properties - PQ2 has low melting/boiling points and is volatile, while R2Q has high melting/boiling points and can conduct electricity when molten. (2) Table 2 shows elements W, Y, and Z. W and Z can form an ionic compound by W donating an electron to form W+ and Z accepting to form Z-. Y and Z form a covalent compound by Y sharing 4 electrons to form 4 single covalent bonds with 4 Z atoms.

1. STRUCTURE QUESTION
PROPERTIES OF IONIC AND COVALENT
Element P Q R
Proton number 6 8 11
Table 1
1 Table 1 shows the proton numbers of three elements P,Q and R.
(a) Write the electron configuration for the ions of elements P,Q and R?
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(3 marks)
(b) i. Draw the electronics arrangement for the compounds formed from the
elements of P and Q.
(2 marks)
ii.What is the bond produced from the formation of the compounds as
in
s (b)(i)
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(1 marks)
(c) i.Draw the electronic arrangement for the compound formed from the
elements Q and R.
(2 marks)
ii.What is the bond produced from the formation of the compound of (c)i?
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(d) State three differences in the properties between the compounds formed as
in the answers of (b)i and (c) i.
1. ____________________________________________________
2. ____________________________________________________
3. ____________________________________________________

2. JAWAPAN
1 (a) Element P : 2.8
Element Q : 2.8
Element R : 2.8
(b) i.
ii. Covalent bond
(c) i.
ii. Ionic bond
(d)
Compound PQ2 Compound R2Q
Melting & boiling point Low High
Votality High Low
Conductivity of electricity Does not conduct Can conduct in the molten
state

3. ESSAY QUESTION
1
Elements Group Period
W 1 3
Y 14 2
Z 17 3
Table 2
(a) With the help of an electron arrangement diagram, explain how two
elements from Table 2 can combine to form
(i) An ionic compound and
(ii) A covalent compound (14 marks)
(b) State the differences between an ionic compound and a covalent
compound. (6 marks)
JAWAPAN
1 (a) (i) - Two elements that form an ionic
compound are W and Z. 2
- Electronic configuration of atom W
is 2.8.1 and electronic configuration
of atom Z is 2.8.7 2
- To achieve the stable octet in the
electron configuration of a noble gas. 1
- An atom W release one electron to
form a W+ ion. 1
- An atom Z accepts one electron to
form a Z- ion. 1
- The positive ions and negative ions
formed are attracted by the strong
electrostatic force of attraction. 1
(ii) - Two elements that form
covalent compounds are Y
and Z 2
- Electronic configuration of
atom Y is 2.4 and Z is 2.8.7 2
- One atom Y contributes four
electrons to be shared with
four atoms of Z. 1
- Four pair of shared electrons

4. form four single covalent
bonds 1
(b) Three differences between an ionic
compound and covalent compound
- An ionic compound has high
boiling and melting point
whereas a covalent
compound has low melting
and boiling point. 2
- An ionic compound is soluble
in water but is insoluble in
organic solvents, whereas a
covalent compound is soluble
in organic solvents but is
insoluble in water. 2
- An ionic compound conducts
electricity in the liquid state
and in aqueous solution
whereas a covalent
compound does not conduct
electricity in any state. 2