Question

What does the word ‘dull’ refer to?

Answer 1

1. Dull: The word 'dull' refers to the fact that substance do not have luster which means they do not have a shining surface.
2. Usually non-metals are dull and non-lustrous.
3. Definition of non-metals: The elements which form negative ions by gaining or accepting electrons are called non-metals.
4. For example, solid non-metals such as Sulphur$\left(\mathrm{S}\right)$ and Phosphorus$\left(\mathrm{P}\right)$ do not have a shining surface so appear to be dull.