Question

What did the dashes on Mendeleev's periodic table represent?elements that are radioactiveelements that were not yet discoveredelements that were being studied at the time

Answer 1

The dashes on Mendeleev's periodic table represented **elements that were not yet discovered**. Mendeleev left gaps in his table for these undiscovered elements, predicting their properties based on the patterns he observed in the table. He correctly anticipated the existence and characteristics of several elements that were later discovered.