Mendeleev was a Russian chemist, who contributed the most for the development of periodic table of elements wherein the elements were arranged on the basis of their fundamental property, the atomic mass and also on the similarity of chemical properties. Only 63 elements were known at his time. He arranged the 63 elements in the increasing order of their atomic masses and found that there was a periodic recurrence of elements with similar physical and chemical properties, He observed that elements with similar properties fall in the same vertical column. These vertical columns are called groups and horizontal rows of elements are called periods. Mendeleev predicted the existence of certain elements not known at that time and named two of them as Eka-silicon and Eka-aluminium.
The elements eka aluminium and eka silicon discovered by Mendeleev later found place in periodic table. Both of these elements belong to:

Options

A. Period 2
B. Group 13
C. Group 14
D. Period 4

Explanation

To determine the groups and periods of the elements Eka-aluminium and Eka-silicon, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements**:
- Eka-aluminium was later discovered to be **Gallium (Ga)**.
- Eka-silicon was later discovered to be **Germanium (Ge)**.

2. **Determine the Group of Each Element**:
- Gallium (Ga) is located in **Group 13** of the periodic table.
- Germanium (Ge) is located in **Group 14** of the periodic table.

3. **Determine the Period of Each Element**:
- Both Gallium (Ga) and Germanium (Ge) are found in **Period 4** of the periodic table.

4. **Conclusion**:
- Both Eka-aluminium (Gallium) and Eka-silicon (Germanium) belong to **Period 4** of the periodic table.

### Final Answer:
Both Eka-aluminium and Eka-silicon belong to **Period 4** of the periodic table.

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