Chapter 15, Problem 11RQ

To determine

The role of atomic number in the periodic table.

Answer to Problem 11RQ

The role of atomic number in the periodic table is to identify the elements and arranging the elements in increasing order of their atomic number.

Explanation of Solution

The atomic number is defined as the number of protons that resides in the nucleus of atoms. So, it is also known as the proton number.

The atomic number is important in the periodic table because of the following reasons given below.

(i) It is used in the identification of elements placed in the periodic table.

(ii) The elements in the modern periodic table are arranged in terms of their atomic number.

(iii) The properties of the elements can be determined by their atomic number and for the stable atom, the total number of protons is equal to the total number of electrons in the atom.

Conclusion:

Therefore, the role of atomic number in the periodic table is to identify the elements and arranging the elements in increasing order of their atomic number.