Malleability, because it shows how adjacent layers of positive ions can move relative to one another while remaining in full contact with the electron sea.

Explanation: Metals with close-packed structures such as copper, gold, silver, zinc, magnesium, etc. are more malleable than those with the bcc structure (tungsten, vanadium, chromium, etc.).

In the close-packed structure, the planes can slip past each other relatively easily. In the bcc structure, there are no close-packed planes, and much greater corrugation between atoms at different levels. This makes it much harder for one row to slide past another.