What were the criteria used by Mendeléev in creating his Periodic Table?

Explanation

### Step-by-Step Solution:

1. **Understanding Mendeleev's Periodic Table**: Mendeleev was a Russian chemist who created one of the first versions of the periodic table. His work laid the foundation for the modern periodic table.

2. **Criteria for Arrangement**: The primary criterion that Mendeleev used to arrange the elements was their **atomic mass**. He believed that the properties of elements are periodic functions of their atomic masses.

3. **Increasing Order of Atomic Mass**: Mendeleev arranged the elements in the **increasing order of their atomic masses**. This means that he listed elements starting from the lightest (lowest atomic mass) to the heaviest (highest atomic mass).

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