Question

Give two examples of non metals that are not ductile

Answer 1

Every material has some measure of ductility. Though some are far less ductile. For example glass has some flex in it where it doesn’t break and returns to its original shape, but no where near as much as rubber.

Materials can be made more ductile, generally thinning it down helps, as seen in glass fibre for communications, but some materials can be “doped” and/or mixed with other materials to adjust it’s properties.

In a more general sense almost every material that would not be described as “brittle” can be considered ductile. Though all materials will break if you apply enough force.