1) A formula unit in chemistry refers to the simplest ratio of ions represented in an ionic compound. It indicates the number of atoms of each element in a compound, providing a snapshot of the compound's composition.
Category/Context
The term "formula unit" is most relevant in the field of inorganic chemistry, specifically when studying ionic compounds and crystal lattices.
Related Terms
- Molecule
- Ionic Compound
- Covalent Compound
- Empirical Formula
- Molecular Formula
Examples/Applications
For example, in the ionic compound sodium chloride (NaCl), one formula unit consists of one sodium ion (Na+) and one chloride ion (Cl-). In calcium chloride (CaCl2), one formula unit includes one calcium ion (Ca2+) and two chloride ions (Cl-).
Chemical Structures/Formula
Formula units are represented as chemical formulae. For instance, the formula unit for sodium chloride is NaCl, and for calcium chloride, it's CaCl2.
Complexity Level
Basic. The concept of a formula unit is fundamental to understanding chemical composition and is typically introduced early in chemistry education.
History
The term "formula unit" is derived from the concept of a chemical formula, which has been used since the 19th century to represent the composition of chemical compounds. source:
- Silberberg, M. S., & Amateis, P. (2018). Chemistry: The Molecular Nature of Matter and Change. McGraw-Hill Education.
- Petrucci, R. H., Harwood, W. S., & Herring, F. G. (2002). General Chemistry: Principles and Modern Applications. Prentice Hall.