Page 28 - PRE-U STPM CHEMISTRY TERM 1

Chemistry Term 1 STPM

Group Element Valence shell configuration
1
3 Sc 3d 4s 2
21
2
4 Ti 3d 4s 2
22
CHAPTER 5 6 23 Cr 3d 4s 2 1
3
V
5
3d 4s
2 7 24 Mn 3d 4s 2
5
25
6
8 Fe 3d 4s 2
26
7
9 Co 3d 4s 2
27
10 Ni 3d 4s 2
8
28
10
11 Cu 3d 4s 1
29
10
12 30 Zn 3d 4s 2
3 They are typical metals with very high melting points and boiling
points.
The f-block Elements
1 Elements with proton numbers 58 – 71 (known as the
lanthanides) and from 90 – 103 (also known as the actinides) are
f-block elements.
1
10 2
2 They have valence shell electronic configuration of f d s to
f d s .
10 2
14
Valence Shell Configuration from the Periodic Table
1 Most chemical recations involve only the valence shell electrons.
Hence, the valence shell electronic configuration of an element is
T
ips
Exam
Exam Tips of utmost importance in predicting the chemical properties of an
element.
2 The valence shell configuration of the representative elements
(Group 1, 2, 13 to 18) can be deduced from its position in the
Periodic Table.
3 The period in which the atom is found corresponds to the Principle
Quantum Number of the valence shell.
4 The group in which the atom is in corresponds to the number of
valence electrons.
5 For example, aluminium (proton number 13) is in Period 3 and
Tips
Exam
Exam T ips Group 13 of the Periodic Table. This means that the outermost
energy level that is filled with electrons is the 3rd shell, and it has
3 (not 13) valence electrons. Hence, its valence shell configuration
The number of valence shell
1
2
electrons of Group 13 to 18 is 3s 3p .
elements is given by: 6 Lead (proton number 82) is in the 6th Period and Group 14. Its
(Group number – 10)
valence shell configuration is 6s 6p .
2
2
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02 Chapter 2.indd 58 3/26/18 3:14 PM