COVALENT BONDING

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COVALENT BONDING
By Joe Sherwood Taylor Leweston School, Dorset
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HOW DOES IT WORK?

• Covalent bonding takes place between non-metals
  atoms only
• Atoms try to attain noble gas structure by
  sharing electrons
• The shared electrons are attracted by both nuclei
  and this attraction forms the covalent bond
• Atoms bonded in this way form molecules

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Chlorine
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CHLORINE
Chlorine has atomic number 17
It has 17 protons in its nucleus
It also has 17 electrons
2 in the inner shell
8 in the next shell
7 in the outer shell
We need 2 chlorine atoms
These atoms can then share electrons to complete
their outer shells
Also written Cl-Cl or Cl2
A chlorine molecule is formed
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Methane CH4
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Carbon has atomic number 6
Hydrogen has just one electron
It therefore has 6 electrons
And we need 4 hydrogens
2 in the inner shell
4 in the outer shell
Now both carbon and all 4 hydrogens have complete
outer shells
4 covalent bonds have been made
Covalent bonds can be shown like this.
Or like this
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Oxygen O2
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Oxygen has atomic number 8
Therefore it has 8 electrons
2 in the inner shell
6 in the outer shell
We need a second oxygen
To complete the outer shell, they each need to
share 2 electrons, so a total 4 electrons are
shared
The covalent bonds can be shown like this.
OO
Or like this
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Most covalent compounds have small
molecules. They are gases, Liquids or solids
with low melting boiling points.
Chlorine Cl2
Iodine I2
Carbon Dioxide CO2
Water H2O
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Covalent bonds can also link atoms in large
networks called Giant Structures.
These have very high melting points and are often
very hard.
Diamond A form of Carbon
Silicon Dioxide (SiO2) Found in sand and quartz
Graphite Another form of Carbon
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CHEMCLINGS
Kits to decorate windows, glass cupboards,
whiteboards etc. Please visit www.chemclings.co.u
k.
The molecular model kit contains 104 pieces to
make models of many different organic and other
molecules.
The electron orbital kit contains 84 pieces to
show the electron arrangement of many different
atoms or molecules.