Name 5 descriptions of a key including mass

I'm assuming you're talking about something like a regular housekey, in which case there are numerous things you can describe!

Its mass: how much it weighs, times the gravity of the system.

Its color: is it silver-colored, or gold, etc.?

Its volume: you could probably calculate this, though it would be hard because it's not a traditional shape, I assume.

Its density: this is mass/volume. It means how many of the atoms are in a given space; how tightly packed the atoms are.

Its tendency to rust / its specific combination of metals or alloys: is it made of copper, tin, steel.. and these are all things that can rust to varying degrees.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.