Question

Metallic luster is explained by.
A) Oscillation of loose electrons.
A) Diffusion of metal ions.
C) Excitation of free protons.
D) Existence of B.C.C lattice.

Answer 1

Hint: First, we understood about luster. In mineralogy luster describes how light is reflected on the surface of minerals. We also remember that the luster is the most important property to determine the identity of a mineral.

Complete step by step answer:
We must remember that the metallic lusters are opaque and reflective. Galena, pyrite, magnetite are some of the examples for metallic luster.
We know that metals have lots of free electrons and the electrons are negatively charged from clouds in a uniform background of positive charge forming high polarized plasma. Plasma is just a dense of charge particles and the distribution of the charge within its volume can be changed by applying an external electromagnetic field. In the absence of any external electromagnetic field the charges in the plasma are uniformly distributed within the metal. So, there are regions within metal that are negatively charged. Thus, incoming light creates an oscillating electromagnetic wave on the surface of metal and disturbs the plasma.

Therefore option A is correct.

Note:
We must know that the lustrous property of the metal is because of the free electrons in them and generally lustrous metals are a good conductor of electricity. For instance, lead is a non lustrous metal and hence it is a poor conductor of electricity. In general luster depends on the minerals reflecting power, degree of transparency and structure. Variations in these properties produce different kinds of luster whereas variation in the quantity of reflected light produces different intensities of the same luster.