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.
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.