Question

Mendeleev noticed that properties of elements usually repeated at regular intervals when the elements were arranged in order of increasing.

Answer 1

Properties of elements usually repeated at regular intervals when the elements were arranged in order of increasing Atomic mass.

The properties of elements are a periodic function of their atomic masses. Mendeleev found that when elements are arranged in the order of increasing atomic mass ,the elements with similar properties occur at regular intervals. Mendeleev's periodic table means that if elements are arranged in the  order of increasing atomic masses then the properties of elements are repeated after regular intervals or period. He arranged 63 elements in the order of increasing atomic masses in horizontal row  but in such a way that elements having similar  properties came directly under one another in the same vertical columns or groups.  

To learn more about Mendeleev's Periodic table please visit:

brainly.com/question/9891527

#SPJ4