Who classified the elements on the basis of fundamental properties of elements like atomic mass?

Explanation

To answer the question "Who classified the elements on the basis of fundamental properties of elements like atomic mass?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Classification Method**: The classification of elements based on atomic mass and fundamental properties is a significant aspect of chemistry.

2. **Historical Context**: In the late 19th century, scientists were trying to organize the known elements in a systematic way.

3. **Key Figure**: The key figure in this classification is Dmitri Mendeleev.

4. **Mendeleev's Contribution**: Mendeleev created the first periodic table, where he arranged the elements in order of increasing atomic mass. He also grouped them based on similar chemical properties.

5. **Predictions**: Mendeleev left gaps in his periodic table for undiscovered elements and predicted their properties based on the trends observed in the table.

6. **Conclusion**: Therefore, the answer to the question is that Dmitri Mendeleev classified the elements based on atomic mass and their fundamental properties.

### Final Answer:
Dmitri Mendeleev classified the elements on the basis of fundamental properties like atomic mass.

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