The atomic mass of sodium (Na) is approximately 22.99 atomic mass units (amu).
Atomic mass is a measurement that indicates how heavy an atom is compared to other atoms. For sodium, this value reflects the weighted average of the masses of all its isotopes, taking into consideration their relative abundances. Sodium-23 is the most abundant isotope, which contributes significantly to this average. Understanding the atomic mass is essential for calculations in chemistry, such as determining the number of moles in a given mass of sodium.