metallic bonding

• What ions do metals always form?

  Cations (positive ions)
• What happens to the outer shell electrons of metal atoms when they form metallic bonds?

  They become delocalized
• Describe the structure of a metal?

  positive metal ions surrounded be a 'sea' of delocalized electrons
• Describe how metal ions held together in metallic bonds?

  The negatively charged delocalized electrons attract the positive metal ions with an electrostatic force
• Describe how the movement of the positive metal ions changes when a metal is heated ?

  the ions vibrate faster (and with a larger amplitude)
• How does the resistance of a metal wire change as temp increases?

  resistance increases
• Explain why the resistance increases when the temp of a metal wire increases?

  the positive metal ions vibrate faster and with a bigger amplitude. More electrons collide with the ions, and it is more difficult for a current to flow.
• Why are pure metals relatively soft and malleable compared to alloys?

  atoms in pure metals are all the same size, and are in regular layers. A force can cause layers to slide over each other
• State 4 properties of metals?

  high tensile strength, malleable and ductile, good conductors of electricity, high melting and boiling points
• Explain why metals have high tensile strengths and melting points?

  There are many strong metallic bonds between electrons and positive metal ions. These take alot of energy / force to break
• Explain why metals are good conductors of electricity?

  There are delocalised electrons that can move freely throughout the metal structure, carrying charge.