Here's why:
* Aluminum is a metal, and arsenic is a metalloid, which exhibits some metallic properties.
* Metallic bonding occurs when metal atoms share their valence electrons in a "sea of electrons." This shared pool of electrons allows for good electrical and thermal conductivity, as well as malleability and ductility.
While the bond is primarily metallic, there is also a degree of covalent character due to the metalloid nature of arsenic. However, the metallic character is dominant.
