What do ionic, covalent and metallic bonds all have in common?
They are strong.
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What is formed when different metals combine?
Alloys
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What do gases, liquids or solids with a low melting and boiling point consist of?
Simple molecules
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Substances that consist of simple molecules have what between their molecules?
Weak intermolecular forces
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What is overcome when a substance melts or boils?
The intermolecular forces
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What do substances that do not conduct electricity consist of? And why?
Simple molecules because the molecules do not have an overall charge.
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What kind of structures do ionic compounds have?
Regular structures / giant ionic lattices in which there are strong electrostatic forces in all directions between oppositely charged ions.
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What do ionic compounds have high melting points and high boiling points?
Because of the large amounts of energy needed to break the many strong bonds.
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How can ionic compounds conduct electricity when melted or dissolved in water?
Because the ions are free to move and carry the current.
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Describe a giant covalent structure.
All the atoms are linked to other atoms by strong covalent bonds and so they have very high melting points.
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Describe the structure of a diamond.
Each carbon atom forms four covalent bonds with other carbon atoms in a giant covalent structure, so diamond is very hard.
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Describe the structure of graphite.
Each carbon atom bonds to three others, forming layers. The layers are free to slide over each other because there are no covalent bonds between the layers and so graphite is soft and slippery.
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How does graphite conduct heat and electricity?
One electron from each carbon atom is delocalised.
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What is the structure of fullereness based on? (fullereness is made from a number of carbon atoms).
Based on hexagonal rings of carbon atoms.
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How do metals conduct heat and electricity?
They have a sea of delocalised electrons, that are free to move about.
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How are metals able to be bent and shaped?
They have layers of atoms that are able to slide over each other.
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What are shape memory alloys?
They can return to their original shape after being deformed.
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Thermosoftening polymers consist of what?
Individual, tangled polymer chains.
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Thermosetting polymers consist of what?
Polymer chains with cross-links between them so that they do not melt when they are heated.
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What are the intermolecular forces like in thermosoftening polymers?
They have very weak covalent bonds and as a result it doesn't take much to break them, so they can be melted easily and re-shaped.
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What are the intermolecular forces like in thermosetting polymers?
The covalent bonds are very strong and stop the bonds from breaking when they are heated.
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What are the size of nanoscience structures?
1-100 nanometres (similar to the size of a few hundred atoms).
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What are nanoparticles/nanoscience used for?
Development of new computers, new catalysts, new coatings, highly selective sensors, stronger and lighter construction materials, and new cosmetics.
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Other cards in this set
Card 2
Front
What is formed when different metals combine?
Back
Alloys
Card 3
Front
What do gases, liquids or solids with a low melting and boiling point consist of?
Back
Card 4
Front
Substances that consist of simple molecules have what between their molecules?
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