Page 27 - PRE-U STPM CHEMISTRY TERM 1

Chemistry Term 1 STPM

Element Valence shell configuration
H 1
1 1s
Li 2s 1
3
Na 3s 1
11
K 4s 1
19 CHAPTER
Rb 1
37 5s
Cs 1 2
55 6s
87 Fr 7s 1
3 Group 2 elements (also called the alkaline earth metals) have two
electrons in the outermost orbital with the configuration of s .
2

Element Valence shell configuration
Be 2s 2
4
Mg 3s 2
12
Ca 2
20 4s
Sr 2
38 5s
Ba 6s 2
56
88 Ra 7s 2

The p-block Elements
1 Elements of Group 13 to Group 18 are known as the p-block elements
because the outermost orbitals that are filled with electrons are the
p orbitals.
[The Group 17 elements are also called the halogens, and the Group
18 elements are called the noble gases.]

2 They have valence shell electronic configurations of s p to s p .
2
1
6
2
Group Representative element Valence shell configuration
2
13 Al 3s 3p 1
13
2
14 Si 3s 3p 2
14
2
15 P 3s 3p 3
15
2
16 S 3s 3p 4
16
2
17 Cl 3s 3p 5
17
2
18 18 Ar 3s 3p 6
The d-block Elements
1 Elements of Group 3 through 12 are known as d-block elements.
2 They have valence shell electronic configurations of d s to d s .
10 2
1 2

57

02 Chapter 2.indd 57 3/26/18 3:14 PM