The periodic table is accredited to Dimitri Mendeleev who published it in 1869 where he arranged the elements according to atomic weight. Later on in 1913, Henry Moosely discovered that the position of an element is better determined by its atomic number, that is the number of protons an atom has. Moosely’s work expanded on Mendeleev’s work and solved some of the issues that Mendeleev’s table had. Since then the Periodic Table has been expanded on and refined as new scientific discoveries are made.