chemical They are the abbreviations and signs used to identify chemical elements and compounds. They were proposed in 1814 by Berzelius to replace chemical symbols and those used by Dalton in 1808 to explain Dalton’s atomic theory.
They derive from the Greek letters of the name of the element and mainly from Latin, although they can sometimes derive from German, English, Russian or French. For this reason, the symbols of elements known since antiquity do not correspond exactly to their current denomination, for example:
- Ag from argentum: Silver.
- Au de aurum: Gold.
- Cu of cuprum: Copper.
- Fe de ferrum: Iron.
As a general rule, the first letter of the symbol is written with a capital letter, and the second (if required) with a lower case. The symbols are not only used as abbreviations when naming the element but also for formulas and equations in order to indicate an amount of it.
The symbol typically represents an atom of the element in a molecule. Atoms have fixed masses, which is called a mole. This allows performing stoichiometric calculations.
It is the representation of the elements that form a compound and the proportion in which they are found, or the number of atoms that form the molecule.
They also provide additional information such as the types of bonds that join these atoms or their distribution in space. There are several types of chemical formulas:
- Molecular formula: Indicates the type of atoms present in a compound and the number of atoms of each class.
- Semi-developed formula: Indicates the bonds between the different groups of atoms. It is widely used in organic chemistry.
- Developed formula: indicates all the links by representing them on a Cartesian plane.
- Structural formula: Indicates the spatial geometry of the molecule.
- Lewis Formula: Indicates the total number of atoms in a molecule with their respective valence electrons.
Difference Between Symbol and Formula
- A symbol is a graphic representation of an element.
- The formulas are built from the relationship of chemical symbols and depend on the composition of the elements and the atoms that compose them.
- Symbols can be derived from Greek, Latin, French, English, Russian, and German.
- Formulas can indicate important information such as the number of atoms present in a molecule and the bonds that join them.