Using the periodic table of elements, Mendeleev successfully predicted the characteristics of elements (gallium, scandium and germanium) that had not been discovered at that time. 19 13 British scientist Moser used cathode rays to hit metals to generate X-rays, and found that the greater the order of atoms, the higher the frequency of X-rays. So he thinks that the positive charge in the nucleus determines the chemical properties of elements, and arranges elements according to the positive charge in the nucleus. Later, it was revised by many scientists for many years before the contemporary periodic table was formed.

20 15 February 3 15, the international union of pure and applied chemistry announced that Russian and American research teams had obtained sufficient evidence to prove that they had discovered the elements 1 15, 1 17 and/kloc-0. In addition, the Federation acknowledged that researchers from Japan Institute of Physical Chemistry had discovered the element 1 13. The two research groups synthesized the above four elements by colliding the lighter nuclei with each other and tracking the decay of the radioactive overweight elements produced afterwards.

On June 8, 20 16, the international union of pure and applied chemistry announced that the synthetic chemical element no. Added 1 13 (abbreviated as Nh), 1 15 (Mc),1/7 (Ts) and 65447 (TS).

Extended data

Element position inference method:

1, and the number of element periods is equal to the number of electron layers outside the nucleus;

2. The ordinal number of the main group element is equal to the outermost electron number;

3. To determine the number of families, we must first determine whether it is the main family or the sub-family. The method is to gradually subtract the number of elements in each period with the atomic number, and the final difference can be determined.

References:

Baidu Encyclopedia-Periodic Table of Elements