5. What is metallic bonding?
6. Why are metals shiny?

Metallic bonding is found in metals and their alloys. When the atoms give up their valence electrons, they form ions. These ions are held together by the electron cloud surrounding them. Metals are shiny because they have a lot of free (i.e. delocalized) electrons that form a cloud of highly mobile negatively charged electrons on and beneath the smooth metal surface in the ideal case. ... In the absence of any external EM field, the charges in the plasma are uniformly distributed within the metal.

Explanation:

In metallic bonding, the electrons are “surrendered” to a common pool and become shared by all the atoms in the solid metal.