H2SO4

Reaction of Fe(III) and Fe(II) with OH

Fe(III) Fe(II)

OHOH

Understanding the electronic structure of an atom

state the meaning of valence electrons determine the number of valence electrons from the electron arrangement of an atom

Electrons arrangement?

Ar

40 Ar 18

2.8.8Proton number : 18

Electron number: 18

Neutron number : 22

Electrons arrangement?

N

14 N 7

2.5

Proton number : 18

Electron number: 18

Neutron number : 22

27 Al 13

Electrons arrangement?

Al

2.8.3

C a

Valence electrons

electron in the outermost shell

Valence electron = 2

Electron arrangement Ca: 2. 8. 8. 2

Determine the number of valence electrons

7 Li 2. : valence electrons = 1 3

31 P 2.8. : valence electrons = 515

24 Mg 2. 8. : valence electrons = 212

EXERCISE

1

5

2

Complete the table below :

Element Proton number ,Z

Electron arrangement Valence electrons

Carbon

Oxygen

Chlorine

Sodium

6

8

17

11

2.4

2.6

2.8.7

2.8.1

4

6

7

1