Chapter 6, Problem 28A

Interpretation Introduction

Interpretation:

The periodic law needs to be defined.

Concept introduction:

In the Mendeleev’s periodic table, elements with similar characteristics present in vertical rows known as groups. The horizontal rows are known as periods. While arranging elements in groups and periods, Mendeleev laid more stress on similar properties and made certain adjustments in their atomic masses.

Answer to Problem 28A

Periodic law states that the chemical and physical properties of elements are periodic function of the atomic numbers of elements.

Explanation of Solution

Dmitri Mendeleev was the scientist who gave the periodic law based on atomic mass of the elements. He had done arrangement of elements identified at that time in order of increasing atomic masses and this arrangement was known as periodic table. But due to some defects this periodic table is not accepted later and new periodic law given which states that arranging elements by increasing atomic numbers causes periodic trends in the physical and chemical properties of the elements.

Conclusion

According to the periodic law, atomic number is the basis of arrangements of elements in the periodic table.