Family: -approximately 16 siblings - dad was teacher and graduated from St. Petersburg's Main Pedagogical Institute. Mom had reopened glass factory to help support her family.
Dmitri married the first time in 1863 where they had 2 children. However they divorced. He remarried a young art student named Anna Popov. Their marriage was happier and they had 4 children.
Mendeleev started by writing the names of the 65 known elements on cards(1 element on each card). He wrote the fundamental properties of each element, including Atomic Mass, on their own cards.
He thought Atomic Mass was important. He saw that the weights increased but he couldn't see a pattern. He moved the cards around but then fell asleep. Upon waking up he knew every pattern.