Materials that conduct heat and electricity well in the solid state result when: 1. metals bond with metals 2. any type of element bonds with any other 3. non-metals bond with metalloids

Metals bond with metals.  
Explanation: A metallic bond is a sharing of electrons between many atoms of a metal element. Metallic bonding is when positive ions (metals) are in a 'sea of negative electrons'. The electrons are delocalised, which means they can move around easily and carry charge, and this enables it to conduct electricity, even in a solid state. The big pool of electrons is like a free-for-all in that any valence electron can move to any atom within the material.