C4 - Metal structure and properties
- Created by: Naomi
- Created on: 23-01-13 20:30
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- Metal structure and properties
- Properties of metals
- Lustrous (shiny)
- Are hard
- Strong metalic bonds
- Have a high density
- Atoms are closely packed together
- Have a high melting point
- A lot of energy is needed to overcome the strong attraction between delocalised elecrons and the positive metal ions
- Have a high tensile strength
- Resistant to attacks by oxygen or acid
- Good conductors of heat and electricity
- Delocalised electrons
- Malleable
- Metallic bonding
- Metals have high melting points and high boiling points, due to their strong metallic bonds
- A lot of energy is needed to break the bonds apart
- When metals conduct electricity, electrons in the metal move
- Metals conduct electricity because delocalised electrons within its structure can move easily
- A metallic bond is a strong electrostatic force of attraction between close-packed positive metal ions and a sea of delocalised electrons
- Metals have high melting points and high boiling points, due to their strong metallic bonds
- Superconductors
- Superconductors are materials that conduct electricity with little or no resistance
- Copper, silver and gold all conduct electiricty well, but do not becaome super conductors
- The electrical resistance of murcury suddenly drops to zero at -268.8 degrees
- Called superconductivity
- When a substance goes from its normal state to a superconducting state it no longer has any magnetic fields inside it
- If a small magnet is rought near the superconductor it is repelled
- If a small permanent magnet is placed above the superconductor it levitates
- The potential benefits of superconductors are:
- Loss-free power transmission
- Super-fast electronic circuits
- Powerful electromagnets
- There needs to be a good deal of development before the true potential of superconductors is realised
- They only work at very low temperatures, which limits their use
- Superconductors that function at 20 degrees need to be developed
- Superconductors are materials that conduct electricity with little or no resistance
- Properties of metals
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