I forgot to mention one more thing about Ernest Rutherford that is truly noteworthy!
Though the periodic table’s "discovery" preceded Rutherford’s discovery of the atomic nucleus by roughly 4 decades, Rutherford’s experiments helped to determine that what was known as the entire positive charge, or atomic number, of the atom, was equal to what was found within a central location of the atom. From this he proposed an inner structure called the nucleus, where the entire positive particulate matter was located within an atom!
In 1870 Dmitri Mendeleev “scooped” Lothar Meyer for publication credit of the periodic table’s hypothesized organization. Not only are elements related physically and chemically depending on atomic number or positive charge, but also, after a certain grouping of elements that increased in atomic number, those similarities would “repeat” in the next grouping of elements. Rutherford, along with fellow scientist H.G. Moseley, performed more experiments that showed that groups of elements with sequential atomic numbers possessed similar nuclear characteristics that could then group them into columns.
Rutherford also discovered that radioactivity was a result of atomic decay. He was quite the prolific experimental scientist, wouldn’t you say? Very deservedly winning the 1908 Nobel Prize for chemistry.