Final answer:
The mole, denoted as 'mol', is the unit used in chemistry to represent the number of atoms, molecules, or formula units. It corresponds to Avogadro's constant, which is 6.022140857 × 10²23 particles per mole, facilitating the translation between microscopic and macroscopic quantities.
Step-by-step explanation:
The unit of measurement used in chemistry to represent atoms, molecules, and formula units is the mole. The mole is a base unit in the International System of Units (SI) for the amount of substance. It is defined by containing exactly 6.022140857 × 1023 of these entities, which is known as Avogadro's constant. Because individual atoms and molecules are so small, using the mole allows chemists to work with quantities that are more meaningful on a macroscopic scale. In any chemical formula, the ratio of the number of moles can be used as a conversion factor to relate macroscopic and microscopic quantities of substances.
The formula unit is the representative particle for ionic compounds, while the representative particle for an element is an individual atom. In molecular compounds, the representative particles are molecules themselves. The mole concept is crucial because it bridges the gap between the atomic scale and the scale at which we perform laboratory work, allowing for the calculation of the formula mass, which is the sum of all atomic masses represented in a substance's formula. This makes the mole an indispensable unit in stoichiometry and other chemical calculations.