Metallic bonding
The particles in a metal are held together by metallic bonds.
High melting and boiling points
Metallic bonds are strong and a lot of energy is needed to break them. This is why metals have high melting points and boiling points.
Conducting electricity
Metals contain electrons that are free to move in the metal structure, carrying charge from place to place and allowing metals to conduct electricity well.
Metallic bonding - Higher tier
Metallic bonding is the strong attraction between closely packed positive metal ions and a 'sea' of delocalised electrons.