Final answer:
Mendeleev is credited with the periodic table due to his foresight in predicting undiscovered elements and leaving gaps for them, which were later validated with the discovery of elements like gallium and germanium.
Step-by-step explanation:
While both German chemist Lothar Meyer and Russian chemist Dmitri Mendeleev proposed similar periodic tables around 1869, Mendeleev is generally given credit for the periodic table for several key reasons. Mendeleev's version was published first, but more importantly, he made bold predictions about the existence of unknown elements that would fit into the gaps he left in his table. His predictions were based on the properties that he expected these elements to exhibit, similar to known elements like aluminum and silicon. When elements such as gallium and germanium were discovered, their properties closely matched Mendeleev's predictions, thus providing substantial support for his periodic table.