State the merits of Mendeleev's classification of elements.

Explanation

### Step-by-Step Text Solution

1. **Grouping of Elements**: Mendeleev's periodic table was structured in a way that grouped elements with similar properties together. He organized the known elements into 8 distinct groups, allowing for easier study and comparison of their characteristics.

2. **Gaps for Undiscovered Elements**: One of the significant merits of Mendeleev's classification was his foresight in leaving gaps in the periodic table. He anticipated that new elements would be discovered in the future and left spaces for these undiscovered elements, which would have similar properties to those already known.

3. **Prediction of Properties**: Mendeleev not only left gaps but also made predictions about the properties of elements that were not yet discovered. For instance, he predicted the existence and properties of elements like Eka-Aluminium (which turned out to be Gallium) and Eka-Silicon (which turned out to be Germanium). This demonstrated his understanding of the periodic trends.

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