Question

Which metal among the followings has the highest packing efficiency?

• A. Iron
• B. Tungsten
• C. Aluminium
• D. Polonium

Answer 1

Answer: (C)

Aluminium

The packing efficiency is the fraction of volume in a crystal structure that is occupied by constituent particles (volume of space occupied by the spheres/total volume). The majority of metals take on either the hcp or bcc structure. Among the given metals $Al$ occupies hexagonal close-packed (hcp) is having 0.74 packing efficiency and other metals form body-centered cubic (bcc) which has 0.68 packing efficiency.
Thus, Aluminium has the highest packing efficiency in comparison to Iron, Tungsten and Polonium.
Hence (C) is correct answer.