Metal structures and properties Flashcards
what is a metal made from?
particles held together by metallic bonds
give 3 properties of most metals?
are hard
good conductors of electricity
have a high density
give an example of a physical property of copper?
its high thermal conductivity
what is copper normally used to make?
the base of saucepans
give an example of a chemical property of gold?
the resistance to attack by oxygen or acids
what are other examples of physical properties of metals?
malleable or ductile
why do some metals have high melting points?
because of their strong metallic bonds between particles
what is aluminium normally used for?
such as in the aircraft industry and also modern cars
what is a metallic bond?
a strong electrostatic force between close-packed posotive metal ions
the particles in a solid metal are:
close together
in a regular arrangement
what happens to metals at very low temperatures?
some metals become super conductors
what can superconductors be used to make?
to levitate magnets and super fast circuits (train tracks)
what are superconductors?
materials that conduct electricity with little or no resistance
what is the temperature at which superconductivity occurs called?
critical temperature
what are the two types of superconductors?
type 1, metals
type 2, alloys
what is removed when a substance goes from its normal state to a superconducting state?
its magnetic fields inside it
give 3 benefits of superconductors?
loss-free power transmission
super-fast electronic circuits
powerful electromagnets
why does a metal conduct electricity?
because de-localised electrons within its structure can move easily
give 2 disadvantages of superconductors?
they only work at very low temperatures
superconductors that function at 20 degrees Celsius need to be developed
give an example of a physical property of a metal?
the high thermal conductivity of copper
give an example of a chemical property of a metal?
the resistance to attack by oxygen or acids shown by gold
why do metals have high melting and boiling points?
because they have strong metallic bonds
what is a metallic bond?
a strong electrostatic force of attraction between close packed posotive metal ions and a sea of delocalised electrons
what are superconductors?
materials that conduct electricity with little or no resistance
what happens when a substance goes from its normal state to a superconducting state?
it no longer has a magnetic field inside it
what happens if a small magnet is brought near the superconductor?
it is repelled
what happens if a small permanent magnet is placed above the superconductor?
it levitates
what are the potential benefits of superconductors?
loss free power transmission
super fast electronic circuits
powerful electromagnets
