In 1863 John Newlands presented a paper, classifying the 56 discovered elements into 11 groups based on similar physical properties. He noted that pairs of similar elements existed which differed by some multiple of eight in atomic weight. In 1864 Newlands published his version of the periodic table and proposed the Law of Octaves, stating that any given element exhibits analogous behavior to the eighth element following it in the table. Dimitri Mendeleev noticed patterns in the properties and atomic weights of halogens, alkali metals and alkaline metals. He also observed similarities between the series CI-K-Ca, Br-Rb-Sr and I-Cs-Ba. In an effort to extend this pattern to other elements, Mendeleev created a card for each element, containing the element's symbol, atomic weight, and chemical and physical properties. As Mendeleev arranged the cards in order of ascending atomic weight, grouping elements of similar properties together, the periodic table was formed. Although Mendeleev's table demonstrated the periodic nature of elements, during the next century, scientists accurately explained why the properties of the elements recur periodically.
Rutherford discovered nuclear charge and this charge, later termed the atomic number, was used to number the elements within the periodic table. Finally variations of the same elements, or isotopes having the same number of protons and electrons but differing numbers of neutrons, were discovered. How did later discoveries change the model of Mendeleev's periodic table to what we accept today?