S3 Chemistry

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S3 Chemistry
Elements
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• An element is a substance which cannot be broken
  down into anything simpler by chemical methods.
• Chemical methods electrolysis heating
• Is water an element ?
• No, it can be broken down into hydrogen and
  oxygen.

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• There are millions of different substances in
  this world.
• However, there are only 109 elements in this
  world.
• So elements can build up into different things.

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(No Transcript)
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• Aluminium (?)
• Sodium (?)
• Silicon (?/?)

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How can you divide the following figures into
groups?
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• There are over 100 elements in this world.
• How can you divide these 100 elements into groups
  ?
• If we want to divide them into two groups
• We can divide them into metals and non-metals.

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Copper is reacted with oxygen and change to green
colour.
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Physical properties of non-metals

• The melting and boiling points of non-metals are
  often ___________.
• The electrical and heat conductivity of
  non-metals are _____________.
• The appearance of non-metals is usually
  _____________ .
• Non-metals are ____________ if they are solids.

low
good
shiny
brittle
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Physical properties of metals

• The melting and boiling points of metals are
  often ___________.
• The electrical and heat _________ of metals are
  _____________.
• The appearance of metals is usually _____________
  .
• Metals can be bent.