Here's why:

* Appearance: Phosphorus is a solid, but it can exist in different forms with varying colors (white, red, black). It doesn't have the characteristic shiny appearance of metals.

* Conductivity: Phosphorus is a poor conductor of heat and electricity, unlike metals.

* Reactivity: Phosphorus is highly reactive, especially the white form, which is flammable and reacts readily with oxygen. This is a typical characteristic of nonmetals.

* Ductility and Malleability: Phosphorus is brittle and cannot be drawn into wires or hammered into sheets, which are properties of metals.

Let me know if you have any other questions!