1. What? Why? When? Which? Where? How? Mod.H U.3 L3&4
Chemical Bonding
What? Why? When? Which? Where? How?
Mod.H U.3 L3&4

2. 3 Types of Bonding
Ionic Bonding
Covalent Bonding
Metallic Bonding

3. Bonding is… the transfer or sharing of electrons
concerned with the Valence Electrons

4. Ionic Bonding
Ionic bonding is an electrical attraction between two oppositely charged atoms.

5. When.. Lose an electron - Atom is Positive
Positive Ion is called Cation
………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
Gain an electron - Atom is Negative
Negative Ion is called Anion

6. Characteristics of Ionic Compounds
1) Crystalline solid at room temp.
2) Have higher melting and boiling points compared to covalent compounds.
3)Conduct electrical current in solution state.
4)Extremely polar (charged) bonds.
5)Most are soluble in water.

7. Magic # The magic number is 8
Every atom wants to gain electrons up to 8, or lose electrons to equal zero, In order to be stable.
Exception= Hydrogen= only needs two electrons

8. Lewis Dot Structure 1) Write the Atomic Symbol
2)Count up the number of valence electrons.
3)Draw a dot around the symbol for each valence electron.

9. Helpful Hint An easy way to check if a bond is Ionic:
One atom must be from group 1, 2, or 13 on the periodic table and the other atom from groups

10. Oxidation Number (Charge)
Group 1 2 13 14 15 16 17 18
Charge +1 +2 +3 -4 -3 -2 -1

11. Covalent Bonds
Covalent Bonds are formed as a result of the sharing of one or more pairs of valence electrons.
Each atom donates half of the electrons to be shared.

12. 2 forms of covalent bonds
1) Polar Covalent - unequal sharing of electrons
2) Non-Polar Covalent – equal sharing of electrons between atoms.

13. Is held together by

14. Single Covalent Bond
A single covalent bond would be the sharing of two electrons between the 2 bonded atoms.
H-H H-Cl F-F
The dash line is symbolic of the bonding pair.
One line equals 2 electrons

15. Covalent Bonding in Chlorine

16. Compare:

17. Double Covalent Bond
A double covalent bond is 2 pairs of electrons being shared.
O=O C=O

18. Triple Covalent Bond
A triple covalent bond is the sharing of 3 pairs of electrons.
N=N C=C C=N

19. Covalent bonds form molecules
A molecule is a neutral group of atoms held together by covalent bonds
Examples: water molecules, oxygen molecules…..

20. WATER MOLECULE

21. Written as
H2O H:O:H O
Single bonds H H

22. DRAW THESE
AMMONIA: NH3
Chlorine gas: Cl2
Methane: CH4

23. Methane CH4

24. NH H : N : H H

25. Properties of covalent bonds:
Low melting point, boiling point
Brittle

26. Shared pair
of electrons
Cl : Cl

27. Metallic Bond The metallic bond occurs only between metal atoms.
In this type of bond the valence electrons overlap and are free to move about
The electron clouds of all metals participating in the bond.
It is similar to a “Sea of Electrons”.

28. A Sea of Electrons

29. Metallic bonds: A ‘sea’ of shared electrons

30. Electrons can move freely
Metallic bonds account for the properties of metal
Conductivity, ductility, malleability, higher temps
Example: paper clips!