Covalent Bonding
LO:
Describe how electrons make a covalent bond (D)
Explain what happens to form a covalent bond (C)
Explain why a compound would have a high or low boiling point (B)
Use the Rutherford model of the atom to explain why covalent bonds occur and represent them in a
diagram. (A/A*)
Starter
Which are metals and non-metals out of…
Na, Cl, Pb, H, N, S, Cu, Fe, C, Ba
How do ionic bonds form ?
Ionic bonds are between Metal and Non-metal.
Covalent bonds are for Non-metals.
The atoms share electrons to get full electron orbits.
What do atoms want ?
Drawing the atoms
Draw the outer most ring.
Fill in the electrons by placing them in UNPAIRED for the first 4 and then pair up for the
rest.
The number of UNPAIRED electrons tells you how many covalent bonds this atom can
make.
How do you know how
many electrons are in the
outer ring ?
Hydrogen
Draw the Hydrogen atom.
Say how many electrons it needs.
Covalent bonding
Fluorine
Draw a dot and cross diagram for the molecule of Fluorine
F2
Explain in no more than 2 sentences why Fluorine will form a diatomic molecule (a
molecule with 2 atoms in it)
Covalent bonding
A covalent molecule can form more than one bond with another atom.
Oxygen
Draw a dot and cross diagram for the oxygen molecule O2
Don’t forget how many electrons are needed in the outer ring.
Also remember that you don’t need to draw any inner rings.
We can represent covalent bonds in a number of ways…
Water
Covalent bonding
Draw these covalent compounds
HCl
NH3
CH4
PCl3
CO2
Make these models
Carbon
HCl
H2O
Hydrogen
CH4
C2H6
Oxygen
CO2
Chlorine
Single bond
Double bond
Sharing electrons