Atomic Volume Definition, Formula

Illustration of an atom


The atomic volume is the volume one mole of an element occupies at room temperature. Atomic volume is typically given in cubic centimeters per mole: cc/mol. The atomic volume is a calculated value using the atomic weight and the density using the formula: atomic volume = atomic weight/density


Another way to calculate atomic volume is to use the atomic or ionic radius of an atom (depending on whether or not you are dealing with an ion). This calculation is based on the idea of an atom as a sphere, which isn't precisely accurate. However, it's a decent approximation.

In this case, the formula for the volume of a sphere is used, where r is the atomic radius:

volume = (4/3)(π)(r3)


For example, a hydrogen atom has an atomic radius of 53 picometers. The volume of a hydrogen atom would be:

volume = (4/3)(π)(533)

volume = 623000 cubic picometers (approximately)