Question

A metal forms cubic crystals. The mass of one unit cell of it is M/NAgram, where M is the atomic mass of the metal and NA is the Avogadro number. What is the type of cubic cell possessed by the metal

Answer 1

The type of cubic cell possessed by the metal A is a simple cubic unit cell.

• There are three types of cubic unit cells, namely - simple cubic cell, body centered cubic cell and face centered cubic cell.
• Simple cubic cell has a contribution of one atom per unit cell.
• Body centered cubic cell has two atoms per unit cell.
• Face centered cubic cell has four atoms per unit cell.
• Atomic mass(M) of an element in grams is the mass of NA atoms of that element.So mass of one atom is equal to M/NA grams.
• Since the given mass of the unit cell is also equal to M/NA grams, it must has exactly one atom in it.
• So the type of unit cell is a simple cubic cell.