1. Rossita Radzak : SASER
CHEMICAL BOND
(a) Group 1 elements react with Group 17 elements to produce compounds that have
high melting points. (4 marks)
The points are:
 Ionic compound produced
 Because involve metal and non metal elements
 Metal atom donates valence electron to form positive ion, non metal atom accepts
electron to negative ion.
 The oppositely charged ions are held together by strong electrostatic force
 More heat energy is needed to overcome the force of attraction.
Formation of ionic compound (metal and non metal)
Sample answer:
1. Electron arrangement of atoms ( Na , 28.1 ; Cl 2.8.7 )/ valence electrons
2. To achieve stable / octet electron arrangement
3. Atom ( Na) releases electron to form sodium ion, Na+
4. Half equation ( Na  Na+ + e)
5. Atom (Cl) gain / accept electron to chloride ion, Cl-
6. Half equation ( Cl + e  Cl- )
7. Oppositely charged ion, Na+ & Cl- are attracted to one another by strong electrostatic
force of attraction to form ionic compound, NaCl
8. Diagram
Formation of covalent compound (nonmetal)
1. electron arrangement of the atom /valence electrons
2. to achieve stable /octet electron arrangement
3. atom (Carbon) contribute 4 electrons while (H) atom contribute 1 electron (for sharing).
4. one ( Carbon ) atom share 4 pairs of electrons with 4 (H) atoms to form covalent
compound , CH4 / ratio
5. diagram
Compare the physical properties of covalent and ionic compound
Covalent compound Ionic compound
Melting and - low - high
boiling Reason: Reason:
- consist of molecules - consist of oppositely charged ions
- weak inter molecular forces - The ions are held together by strong
- less energy needed to overcome electrostatic forces.
the weak forces - More heat energy needed to overcome the
strong forces.
Electrical - consist of molecules - consist of oppositely charged ions
conductivity -does not conduct electricity - conduct electricity in molten and aqueous
solution.
- in molten and aqueous solution, ions can
move freely.