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.
One thing that Mendeleev did not predict was the discovery of a whole new Group of elements, the noble gases, by the Scot William Ramsay and co-workers during the last decade of the 19 th century (see The discovery of new elements).