Eponymous terms play an important role in STEM education. This research focuses on the current state of Mendeleev eponyms in the context of education and ethnocentrism, addressing their usage in various languages, their educational value, cases of questioned priority and copyright violation in Mendeleev major eponyms--periodic table and periodic system. 106 chemistry textbooks in 4 languages including Soviet-time and current Russian textbooks were perused to identify and trace Mendeleev eponyms over 1924-2016. Advanced Google Search with queries in Belarusian, English, Latvian, Polish, Russian, and Ukrainian was conducted to evaluate online presence of eponyms "Mendeleev periodic table" and "Mendeleev periodic system." It was found that while Mendeleev eponyms occur generously on the Internet, periodic table and system with Mendeleev's name attached are seldom used on non-Russian webpages. Most Mendeleev eponyms were made up in the USSR and remain popular and Russia, which can be explained within the framework of ethnocentrism as a ruling tendency. Recognizing Mendeleev's priority, Flinn and Ross's periodic systems can be considered plagiarized; a few factors might favor their emergence, but ethnocentrism is unlikely to be one of them. Mendeleev eponyms remain valuable assets for science education, acting as shortcuts to the history of science and actualizing interdisciplinary connections. [For the full proceedings, see ED629086.]