Question

The metallic lustre exhibited by sodium is explained by

(A) Diffusion of sodium ions

(B) Oscillation of loose electrons

(C) Excitation of free protons

(D) Existence of body–centered cubic lattice

Answer 1

@JFraser Can you help ?
I know the answer is B ,but have no idea why..

Answer 2

most metals are shiny, probably because of the "sea" of d-orbtial electrons available in the transition metals (like silver or gold) sodium doesn't have d-orbitals, but its valence electron is probably held on loosely, making it easy to move around

Answer 3

Okay ..Thank you so much! :)

Answer 4

@Diyadiya Actually, the explanation goes like this --->as @jfraser said, there are loose-electrons in the 'sea' all the time, mostly at the surface. And since they aren't bound so well to the kernel, they oscillate at a collective frequency (in a phased manner), and this oscillation prevents any light from being absorbed, or rather passing through 'into' the metal. So, as most of the light is reflected back, the surface appears lustrous.

Now if you mean, why is sodium (or any other s-block metal) not AS lustrous as any other d-block metal (like copper, etc), the reason is that s-block elements have their loose electrons bonded relatively more closely bonded to the kernel, than the d-block elements' loose electrons (due to lesser no. of valence electrons that are to handled by the nucleus). So, they are unable to oscillate as well as the loose electrons in case of the d-block elements, and hence block (reflect) lesser light comparatively. this makes them appear less lustrous than their d-block counter-parts!!