On what basis did Mendeleev arrange the elements in his periodic table?

On what basis are they arranged now?

State whether the following statements are true or false:

(a) Newlands divided the elements into horizontal rows of eight elements each.

(b) According to Mendeleev’s periodic law, the properties of elements are a periodic function of their atomic numbers.

(c) The elements in a group have consecutive atomic numbers.

Name the Russian chemist who said that the properties of elements are a periodic functions of their atomic masses.

Rewrite the following statements after correction, if necessary:

(a) Group have elements with consecutive atomic numbers.

(b) Periodic are the horizontal rows of elements.

(c) Isotopes are the elements of the same group.