See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

(A) 2-D-hexagonal packing 2 2 3 R R 6 3 Packing efficiency = 3(2R) 6 4      (B) simple cubic 3 3 4 1 R 3 a    a 2R  3 3 4 6 R 3 H.C.P. (3D) 24 2R     3 3 4 4 R 3 F.C.C. (3D) (2 2R)    