Senior Congregate Care. What is congregate housing? Congregate housing is an environment thatâs designed to cater for the housing needs of seniors and disabled persons. Residents of a congregate housing complex have private apartments but share a common dining room, kitchen facilities, and other amenities. The purpose of this arrangement is to allow seniors to continue living an independent life although assisted with such tasks like cooking.
The Russian chemist Dmitri Mendeleev was the first scientist to make a periodic table similar to the one used today. Mendeleev arranged the elements by atomic mass, corresponding to relative molar mass.
Another person to propose a periodic table was Lothar Meyer, who published a paper in 1864 describing 28 elements classified by their valence, but with no prediction of new elements. After becoming a teacher, Mendeleev wrote the definitive textbook of his time: Principles of Chemistry (two volumes, 1868â1870).n 1907, Mendeleev died at the age of 72 in Saint Petersburg from influenza. The crater Mendeleev on the Moon, as well as element number 101, the radioactive mendelevium, are named after him.