Q1: There are one octahedral void and __________ tetrahedral void in the closest packing of atoms.

ANS:B - two

In the closest packing of atoms, each octahedral void is surrounded by six atoms, while each tetrahedral void is surrounded by four atoms. Since the arrangement of atoms creates two tetrahedral voids for every octahedral void, there are two tetrahedral voids in addition to each octahedral void. This results in a total of two tetrahedral voids for every octahedral void in the closest packing of atoms.