1. Formation of compounds
Chemical Bonding
Formation of compounds

2. What happens when a piece of burning sodium is placed in a gas jar of chlorine?+
sodium chloride

3. Sodium gives 1 electron to chlorine
Before Bonding Na Cl
sodium = 11 electrons :
2, 8, 1
chlorine = 17 electrons :
2, 8, 7
Sodium gives 1 electron to chlorine

4. Na+ = 2 , 8 Cl - = 2, 8, 8 Cl Na sodium ion 11 protons 10 electrons
Charge
Na+ = 2 , 8
chloride ion
17 protons
18 electrons
Charge
Cl - = 2, 8, 8

5. Chemical formula of sodium chloride is NaCl
After Bonding Cl Na
This type of bonding is known as ionic bonding because the metal atoms transfer electron(s) to non-metal atoms and ions are formed.
Sodium atom loses an electron to form sodium ion Na +
Chlorine atom gains an electron to form chloride ion Cl-
Chemical formula of sodium chloride is NaCl

6. When metal meet non-metals, the sparks will fly “Give me the electrons
When metal meet non-metals, the sparks will fly “Give me the electrons!” non-metal do cry “you got a deal!” the metal responds The ions attract to form their bonds.

7. Lithium + fluorine  lithium fluoride
Before Bonding Li F
lithium = 3 electrons :
2, 1
fluorine = 9 electrons :
2, 7
Lithium gives 1 electron to fluorine

8. Li+ = 2 F - = 2, 8 F Li lithium ion 3 protons 2 electrons Charge + 1
fluoride ion
9 protons
10 electrons
Charge
F - = 2, 8

9. Chemical formula of lithium fluoride is LiF
After Bonding F Li
Lithium atom loses an electron to form
lithium ion Li +
Fluorine atom gains an electron to form
fluoride ion F-
Chemical formula of lithium fluoride is LiF

10. What happens when a piece of magnesium is burnt in air?
magnesium oxygen  magnesium oxide

11. Magnesium gives 2 electrons to oxygen
Before Bonding Mg O
magnesium = 12 electrons :
2, 8, 2
oxygen = 8 electrons :
2, 6
Magnesium gives 2 electrons to oxygen

12. 2+ 2- Mg 2+ = 2 , 8 O 2- = 2, 8 Mg O magnesium ion 12 protons
10 electrons
Charge
Mg 2+ = 2 , 8
oxide ion
8 protons
10 electrons
Charge
O 2- = 2, 8

13. Chemical formula of magnesium oxide is MgO
After Bonding O Mg 2+ 2-
Magnesium atoms lose 2 electrons to form magnesium ions Mg 2+
Oxygen atoms gain 2 electrons to form oxide ions O 2-
Chemical formula of magnesium oxide is MgO

14. Cl Mg Cl
Mg = 12 electrons:
2, 8, 2
Cl = 17 electrons : 2, 8, 7

15. 2+ Cl Mg Cl
Mg 2+ = 2 , 8
Cl - = 2 , 8, 8

16. Magnesium chloride is MgCl2
After Bonding Cl Mg 2+ 2
Magnesium lost 2 electrons to form
magnesium ions Mg 2+
Each chlorine atom gained an electron to form chloride ions Cl –
Magnesium chloride is MgCl2

17. Sodium oxide O Na
O : 8 electrons :
2, 6 Na
Na: 11 electrons :
2, 8, 1

18. 2- O Na
Na + = 2 , 8
O 2- = 2, 8 Na

19. 2 2- Sodium oxide is Na2 O O Na
After Bonding Na O 2- 2
Each sodium atom lost an electron to form
sodium ions Na +
An oxygen atom gained 2 electrons to form an
oxide ion O 2-
Sodium oxide is Na2 O

20. Potassium sulphide S K K S : 16 electrons : 2, 8, 6 K: 19 electrons :
2, 8, 8, 1

21. 2- S K
S 2- : 2, 8, 8
K+ : 2, 8, 8 K

22. Potassium sulphide is K2 S
After Bonding K S 2- 2
Each potassium atom lost an electron to form
potassium ions K +
A sulphur atom gained 2 electrons to form sulphide ion S 2-
Potassium sulphide is K2 S

23. Al = 13 electrons:
2, 8, 3 F Al F F
F = 9 electrons : 2, 7

24. Al 3+ : 2, 8 F 3+ Al F F
F- : 2, 8

25. Aluminium Fluoride is AlF3
After Bonding F Al 3+ 3
Aluminium atom lost 3 electrons to form
aluminium ions Al 3+
Each fluorine atom gained an electrons to form fluoride ion F –
Aluminium Fluoride is AlF3

26. Metals transfer electrons to non-metal forming ions
Summary Li Na K Mg Ca Al F Cl O S
Metals transfer electrons to non-metal forming ions

27. Predict the formulas for the following ionic compounds:
Potassium bromide
Lithium oxide
Magnesium sulphide
Sodium iodide
Aluminium chloride
Calcium fluoride
KBr
Li2O
MgS
NaI
AlCl3
CaF2