Question

How did Mendeleev predict the existence of some elements yet to be discovered elements in his periodic table?

• A. Gaps
• B. Atomic number
• C. Mass number
• D. None of the above

Answer 1

The correct option is A Gaps

Professor Dmitri Mendeleev published the first periodic table of the atomic elements in 1869 based on properties which appeared with some regularity as he laid out the elements from lightest to heaviest. When Mendeleev proposed his periodic table, he noted gaps in the table, and predicted that as-of-yet unknown elements existed with properties appropriate to fill those gaps.