Non-mosaic Down syndrome is a genetic disorder. Most people with non-mosaic Down syndrome have three copies of chromosome 21 in all of their cells (chromosome 21 trisomy); some have an extra copy of chromosome 21 attached to a different chromosome in all of their cells (chromosome 21 translocation).
Making the world better, one answer at a time. Stanislao Cannizzaro, an Italian chemist who worked with Dmitri, inspired Dmitri Mendeleev to come up with his creative ideas. Atomic Weight also inspired Mendeleev.
The modern periodic table, based on atomic number and electron configuration, was created primarily by a Russian chemist, Dmitri Ivanovich Mendeleev, and a German physicist, Julius Lothar Meyer, both working independently. They both created similar periodic tables only a few months apart in 1869. Mendeleev created the first periodic table based on atomic weight. He observed that many elements had similar properties, and that they occur periodically. Hence, the table's name. His periodic law states that the chemical and physical properties of the elements vary in a periodic way with their atomic weights.