The periodic table is a list of man made and naturally occurring elements arranged by an increasing atomic weight and usually in horizontal rows (periods) with similar atomic structure and the chemical makeup then appearing in vertical rows.
There are 118 known elements listed on the (modern) periodic table from the air we breathe to the carbon the world is made up of, and everything in between, these are displayed in 8 main groups and comprise of:
Alkali metals (group 1)
Alkaline earth metals (group 2)
Coinage metals (not an IUPAC approved name) (Group 11)
Pnictogens (not an IUPAC approved name) (group 15)
Chalcogens (group 16)
Halogens (group 17)
Noble gases (group 18)
There is a 119th hypothesized chemical element known as eka-francium or element 11, it has a symbol name of Ununennium and Uue as the symbol respectively. The temporary name and symbol with only be recognized officially after the actual discovery of this element is announced.
Thankfully for us the classification of these elements make it easier to identify components by their overall and respective broken down groups.
Source: © Science Photo Library
Mendeleev’s handwritten periodic table from 1869 – with gaps