Question

State true or false. Non-metals have lustre.

Answer 1

Hint: We have to remember that the property of elements that shows how well the element reflects light is known as lustre. Lustre is shown by solid surfaces when they reflect incident light. This is because of the presence of free electrons.

Complete step by step answer:
As we know that the luster is the property of minerals that shows what proportion or how well the mineral reflects light. Lustre has two categories; metallic and non-metallic.
Most of the non-metals are not solid and don’t have any crystalline surface. Normally lustre is shown by the surface of a solid by reflecting an incident light. However, there is an exception, two of the non-metals show lustre; they are diamond and iodine.
Non-metals vary greatly in appearance. They don’t have lustre. We have to remember that the non-metals don't have any free electrons, light falling on non-metals doesn’t reflect due to this reason non-metals are not shiny.
Therefore, the solution to this present question is false.

Additional Information:
As we know that the screening effect is additionally referred to as the shielding effect. The phenomenon which occurs when the nucleus reduces its forces of attraction on the valence electrons, due to the presence of electrons in the inner shell is known as screening effect. Non-metals are non lustre in nature, with the exception of two elements.

Note:
We have to remember that the Lustre is basically due to free electrons. As we move down the group, the size of the atoms increase and more shells are added. So due to screening effect, effective nuclear charge is less and hence electrons are loosely bound. Therefore, non-metals are lustre in nature.