What is the basic difference in approach between the Mendeleev's periodic law and the Modern periodic law?

Explanation

To answer the question regarding the basic difference in approach between Mendeleev's periodic law and the modern periodic law, we can break down the differences into several key points:

### Step-by-Step Solution:

1. **Basis of Arrangement**:
- **Mendeleev's Periodic Law**: The periodic table was based on the atomic mass of the elements. Mendeleev arranged the elements in order of increasing atomic mass.
- **Modern Periodic Law**: The modern periodic table is based on the atomic number of the elements. Elements are arranged in order of increasing atomic number.

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