Question

Lustre of metal is attributed to:
(A) Loosely bound electrons present in the valence shell of the metal atoms
(B) Strong electrostatic force of attraction between electrons and metal kernels
(C) Omnidirectional nature of metallic bond
(D) None of the above

Answer 1

Hint : Lustre is the shine that metals have on their surface. This is caused by the light-reflecting off the metal particles. Think about what properties and what contents of metals can cause such reflection of light.

Complete Step By Step Answer:
Lustre is the appearance of a substance – mainly metals and minerals – in terms of its light-reflective qualities. Electrons have the property of absorbing and emitting energy.
In doing this, they get excited to higher energy levels when they absorb energy and fall back down to their original level when they emit it. In the same way, the loosely bound electrons present in the valence shell of metal atoms give metal substances this property. Lustre of metals is attributed to the loosely bound electrons present in the valence shell of the metal atoms. When light is shone on the surface of the metal, these valence electrons absorb small amounts of energy and become excited into one of its many empty orbitals.
The electrons then immediately fall back down to lower energy levels and emit light.
Therefore, the answer is option (A).

Additional Information:
One of the other major properties of metals – conductivity – is also due to the presence of valence electrons in metal atoms. The electrons are free to move in the solid lattice. These mobile electrons act as charge carriers and conduct electricity and act as conductors in the conduction of heat. The valence electrons in metal atoms are also responsible for other properties of metals such as malleability and ductility.

Note :
You need to learn the properties of the electrons in the valence shell of any atom. Understanding what those electrons do will help you answer such questions. These electrons are involved in structural properties, conduction of both heat and electricity, and they are also involved in the absorption and emission of light.