Here's why:

* State of matter: Bromine is a liquid at room temperature. Liquids are generally poorer conductors of heat and electricity than solids.

* Atomic structure: Bromine is a nonmetal. Nonmetals have a tendency to hold onto their electrons tightly, making it difficult for electrons to move freely and conduct electricity. They also have weak intermolecular forces, which contribute to poor heat conduction.

* Electrons: Bromine atoms have a relatively high electronegativity, meaning they attract electrons strongly. This makes it difficult for electrons to move freely, which is necessary for good conductivity.

In contrast: Metals are good conductors of heat and electricity because they have free electrons that can move easily throughout the material.