1. Poor conductors of heat and electricity: Nonmetals generally do not conduct heat or electricity well. This is because they lack free-moving electrons that can carry charge.

2. Brittle and non-malleable: Nonmetals are often brittle, meaning they break easily when subjected to force. They also tend to be non-malleable, meaning they cannot be hammered or shaped into different forms.

3. Dull appearance: Most nonmetals have a dull appearance, unlike metals which are often shiny. There are exceptions, like sulfur which can be yellow, but generally, they lack the luster seen in metals.