Atomic volume

The atomic volume is the volume occupied by one mole of an atom of the element under consideration. It is obtained according to the following equation:

Va=maρ ρ ,{displaystyle V_{a}={frac {m_{a}}{rho },}

• V_a: volume of the atom,
• m_a: mass of the atom,
• ρ: density

It is measured in units of volume per mole (for example, cm³/mol).

Considerations when applying this formula:

• In gaseous elements, the fluid density is taken at its boiling point.
• In solids with alotropic molecular structures (such as sulphur), the most stable is chosen.
• In solids with alottropic crystal structures, the density of which has coordination number is taken 6.

Atomic volume increases with atomic number in elements of the same group (for example, potassium will be greater than sodium, etc.)

The groups with the largest atomic volume are the s-block metals, then the non-metals, and finally the transition metals. In a period it decreases towards the right of the periodic table, except in the elements copper, zinc and gallium where the volume and atomic volumes have a relationship with chemical periodicity.

Therefore, the elements with the smallest atomic volume are those of group 5.