What are Atoms?
An atom is the smallest, indivisible unit of matter.
History of Atoms
At the end of the 18th century, the atomic theory put forth by John Dalton helped shed some light on the concept of an atom. At that time, not many elements were known. Hence, scientists preferred allocating symbols to known elements.
Historic representation of atoms
With time, the use of symbols made it difficult to use them in representations of complex reactions. To solve this problem, a Swedish chemist, Jöns Jacob Berzelius, suggested using 2 letters from the name of the elements to represent them. The names of the elements were given based on their appearance, properties or the place where they were first discovered.
How are atoms represented today?
- Continuing with the idea of Berzelius, the atoms of an element are symbolically represented with their first letter written in upper case. For example, hydrogen is denoted by ‘H’ and carbon by ‘C’.
- For other elements that begin with the same alphabet, we use the succeeding letter, written in lowercase. A few examples of atoms that are represented this way are helium, represented by ‘He’, aluminium by ‘Al’, and cobalt by ‘Co’.
- Some elements can also have symbols where the second letter is not immediately
the next one. For example, chlorine represented by ‘Cl’.
- A few elements are given names in Greek and Latin. For example, sodium is written
as ‘Na’ because its Latin name is natrium.
- The modern-day nomenclature is decided by IUPAC -International Union of Pure and Applied Chemistry. It is a committee that sets up various rules and conducts in chemistry—right from naming the element to setting up various standards and functions.