Q1 of 181 Page 281

On what basis are they arranged now?

Now they are arranged on the basis of their atomic number. The number of protons in the nucleus of the atom is the atomic number of that element.

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

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.

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.