Final answer:
A mole contains Avogadro's number of particles, which is exactly 6.022 x 10^23, regardless of the nature of the particles (atoms, molecules, or formula units).
Step-by-step explanation:
The number of particles in a mole is Avogadro's number, which is precisely 6.022 × 1023. This applies to any particle type, whether they're atoms, molecules, or formula units. Avogadro's number provides a way to equate the mass of a substance in grams to the number of its constituent particles, which is pivotal for stoichiometric calculations in chemistry.