February 18-24, Tomsk will host the Week of Science. It is a series of open science-popular events for Tomsk citizens of all ages. A number of events will be held in TPU. On February 21, one will conduct the open lecture from the Periodic System to the Present Day. It will be dedicated to the research of Dmitry Mendeleev, taking into account the modern possibilities of science. The lecture is free for all.