Dot-Cross Diagrams

Report
The New Progress Tracker
For each section of the module you will
be given a progress tracker booklet. This
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a section of the specification is complete
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F332 – Chemistry of Natural Resources
• This module is made up for three main topics
▫ Elements from the Sea
▫ The Atmosphere
▫ Polymer Revolution
• This is the biggest module this year, worth 50%
of your AS level, therefore 25% of the full A-level
Dot-Cross Diagrams
And Introducing Dative Bonding
Objectives
Be able to...
• Draw simple dot-cross diagrams for ionic and
covalent compounds
• Describe and draw dative covalent bonds
• Link the types of bonding to physical properties
of chemicals
Specification...
Where this comes from...
Types of bonding
There are three types of bond that can occur between atoms:

an ionic bond occurs  a covalent bond
between a metal and
occurs between two
non-metal atom (e.g.
non-metal atoms (e.g.
NaCl)
I2, CH4)

a metallic bond
occurs between atoms
in a metal (e.g. Cu)
Representing ionic bonding
Covalent bonding
Task
• Draw dot-cross diagrams for:
1.
2.
3.
4.
5.
Lithium fluoride
Calcium chloride
Water
Ethene
Phosphorus pentachloride (beware this does not
obey the octet rule)
Lithium Fluoride
Calcium chloride
Water
Ethene
Phosphorus Pentachloride
Co-ordinate bonding
Examples of co-ordinate bonds
Task
• Explain what a dative covalent bond is and how
it is formed. Give examples of molecular ions
containing dative covalent bonds.
• Draw dot-cross diagrams for:
▫ Hydroxonium ion
▫ Ammonium chloride
Hydroxonium Ion
Ammonium Chloride
Bonding and Properties
• How do the properties of chemicals differ within
different types of bonding?
• Consider:
▫
▫
▫
▫
▫
Melting and Boiling Points
Solubility
Thermal and electrical conductivity
Hardness
Any others you can think of...
• Discuss.
Bonding and Properties
Property
Melting and
Boiling Points
Solubility
Thermal and
electrical
conductivity
Hardness
Other points
Ionic
Simple
Molecular
Giant Covalent

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