1. Starter S-63
What is an ionic bond?
What is a covalent bond?

2. Chapter 8
Covalent Bonding

3. Chapter 8
8.1 Molecular Compounds

4. 8.1 Molecular Compounds
Covalent Bond – held together by sharing electrons
Molecule – a neutral group of atoms joined together by covalent bonds
H2 Covalent Bond

5. 8.1 Molecular Compounds
Diatomic Molecules – the following atoms in their elemental state are molecules consisting of two atoms
Hydrogen – H2
Nitrogen – N2
Oxygen – O2
Fluorine – F2
Chlorine – Cl2
Bromine – Br2
Iodine – I2

6. 8.1 Molecular Compounds Molecule Example – Water
Bonds within at atom are very strong
Between molecules much weaker
results in lower
melting and
boiling points
Water

7. 8.1 Molecular Compounds
Molecular formula – shows the number of atoms of each element that are in a molecule

8. 8.1 Molecular Compounds
The formula does not show structure

9. Starter S-68
Which is the most interesting element that you have heard a presentation on?
Why?

10. 8.2 The Nature of Covalent Bonding
Chapter 8
8.2 The Nature of Covalent Bonding

11. 8.2 The Nature of Covalent Bonds
In covalent bonds, electrons sharing usually occurs so that atoms attain the electron configuration of noble gases
Hydrogen gets configuration of He
Carbon gets configuration of Ne
Chlorine – Ar
Nitrogen – Ne
Oxygen - Ne

12. 8.2 The Nature of Covalent Bonds
Single Covalent Bond
Share one pair of electrons

13. 8.2 The Nature of Covalent Bonds
Bond dissociation energy – defined as the energy needed to break a bond
The larger the bond dissociation energy, the stronger the covalent bond
A C-C bond usually has about 347kJ/mol
Bond Energy

14. 8.2 The Nature of Covalent Bonds
There are some exceptions to the octet rule

15. Starter S-69 What compound is formed from Carbon and Chlorine?
What compound is formed from Oxygen and Carbon?

16. 8.3 Polar Bonds and Molecules
Chapter 8
8.3 Polar Bonds and Molecules

17. 8.3 Polar Bonds and Molecules
Bond Polarity
Some atoms attract electrons more than others
Atoms with
greater
Electronegativity
attract more

18. 8.3 Polar Bonds and Molecules
If atoms have the same electronegativity then they perfectly share electrons
This only occurs if the two
atoms are the same element
If they have different electronegativety values, then the electron stays around one atom more than the other

19. 8.3 Polar Bonds and Molecules
The result is a polar
Bond
H-H is non-polar
H-Cl is polar

20. 8.3 Polar Bonds and Molecules
Molecules are polar if they are not symmetrical
These molecules can be attracted to each other

21. 8.3 Polar Bonds and Molecules
Symmetrical molecules are nonpolar molecules
There are polar bond
But they cancel out s+ s-