What are diamond and graphite and what structures do they have?
They are allotropes of carbon and have giant covalent structures.
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What causes the physical differences in their structures?
Both are only composed of carbon but due to the differences in bonding arrangements they are physically different.
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What do giant covalent structures contain?
Contain billions of non-metal atoms, each joined to adjacent atoms by covalent bonds forming a giant lattice structure.
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How do the atoms bond in diamonds?
-Each carbon atom bonds with four other carbons, forming a tetrahedron.
-All covalent bonds are identical, very strong and there are no intermolecular forces.
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How do the atoms bond in graphite?
-Each carbon atom in graphite bond to three other atoms forming layers of hexagons, leaving one free electron per carbon atom delocalised.
-Covalent bonds within the layers are very strong but the layers are attracted to each other by weak intermolecular
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What are the physical properties of diamonds?
Does not conduct electricity.
Very high melting points.
Extremely hard and dense.
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Why can't diamonds conduct electricity?
Because there are no freely moving charged particles to carry the current thus it cannot conduct electricity.
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Why do diamonds have high melting points?
Because the carbon atoms are arranged in strong fixed covalent bonds- a very large amount of heat energy is needed to break the lattice.
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What are the uses of diamond?
-Jewellery due to it's sparkling appearance.
-Cutting tools due to it's hardness. (Hardest naturally occurring mineral)
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What are the properties of graphite?
Conducts electricity.
High melting points.
Soft and slippery.
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Why can graphite conduct electricity?
It can conduct electricity because in it's structure there are free (delocalised) electrons between the layers that are free to move through the structure and carry charge.
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Why does graphite have a high melting point?
Because of strong covalent bonds between the adjacent atoms so a very large amount of heat energy is needed to break the lattice.
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Why is graphite slippery and smooth?
Because the layers of the structure are connected to each other by weak forces only, hence the layers can slide over each other.
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What are the uses of graphite?
-Used in pencils, used as an industrial lubricant.
-Or used to make non-reactive electrodes for electrolysis.
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What is silicon (IV) oxide?
It is a macromolecular compound which occurs naturally as sand and quartz.
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How are the atoms bonded in silicon oxide?
Oxygen atoms form covalent bonds with 2 silicon atoms and each silicon atom in turn forms covalent bonds with 4 oxygen atoms.
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With what other element does silicon oxide share properties?
With diamond.
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What are the uses of silicon (IV) oxide?
Used to make sandpaper.
Used to line the inside of furnaces.
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What are the structures of metal atoms?
They are held together strongly by metallic bonding in a giant metallic structure.
They move freely between the positively charged metal ions like a sea of electrons.
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What happens within a metallic lattice?
The metals lose an electron from the outer shell to become a positively charged ion.
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What happens to the outer shell electron?
They are said to be delocalised, it no longer belongs to a particular metal atom.
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Why are metallic bonds strong?
Metallic bonds are strong due to strong forces of attraction between positive metal ions and the sea of negatively charged delocalised electrons.
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What are the properties of metals?
They have high melting and boiling points.
They are strong.
They can conduct heat and electricity.
They are malleable and ductile.
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Why do metals have high melting and boiling points?
Because metals have strong metallic bonds- lots of heat energy required to break these bonds.
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Why can metals conduct electricity?
Because the structures of metals have free moving electrons available to move through the structure and carry a charge.
Electrons entering one end of the metal cause a delocalised electron to displace itself from the other end.
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Why are metals malleable and ductile?
Because layers of positive ions can slide up over one another and take up different positions.
Metallic bonds are thus not broken and as a result metals are strong but flexible.
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What are the uses of metal?
They can be hammered into different shapes or can be drawn into wires.
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Other cards in this set
Card 2
Front
What causes the physical differences in their structures?
Back
Both are only composed of carbon but due to the differences in bonding arrangements they are physically different.
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