The Atomic Number, Dmitri

The first explicit use of atomic number is attributed to John Newlands, who arranged his 1864 table of elements by the number of the element in the order of their equivalents using Cannizzaro s system. At the time, Professor George Carey Foster humorously enquired of Mr. Newlands whether he had ever examined the elements according to the order of their initial letters.  

The fact that atoms have their identities locked inside their nuclei was only discovered at the beginning of the twentieth century. The Curies first postulated that radiation emitted from uranium and other radioactive substances was partic-ulace in nature. In 1906, Rutherford and Geiger determined a value for the charge-to-mass ratio of the a particle that was one-half that for the hydrogen ion Therefore, the a particle could have been either or The latter 

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