Final answer:
In crystal structures, closest packing is approximated by layers of spherical atoms of identical size, forming hexagonal closest packed or cubic closest packed arrangements. option a is correct
Step-by-step explanation:
option a is correct Closest packing structures in crystals can be approximated by layers of spherical atoms of identical size. Hexagonal closest packed (HCP) and cubic closest packed (CCP) structures are two examples wherein atoms are packed as compactly as possible. HCP consists of two alternating layers labeled as ABABAB..., while CCP consists of three alternating layers arranged in the sequence ABCABCABC.... In three-dimensional space, these close-packed structures allow for the maximum amount of interaction between atoms, leading to more energetically stable structures commonly seen in metallic, atomic, and simple ionic crystals.
The closest packing structures can be approximated by layers of identical size spherical atoms. In hexagonal closest packing, the layers alternate with an ABABAB... pattern, while in cubic closest packing, the layers alternate with an ABCABCABC... pattern. These packing structures are the most efficient in terms of packing the maximum amount of atoms together and minimizing empty space between them.