An element was predicted by MENDELEEV as Eka-Aluminium and it was discovered later on. The name of that element is:

Question

Accepted Answer

The correct option is (1):

Dmitri Mendeleev, while developing his periodic table, left gaps for elements that had not yet been discovered but whose properties he could predict based on their position in the table. He used the Sanskrit prefix "eka-" (meaning "one") to name these predicted elements, indicating that they were "one place away" from a known element in the same group. For example, he predicted an element he called "Eka-Aluminium," which would lie beneath aluminium in the periodic table. His predictions for Eka-Aluminium included its atomic mass, density, melting point, and the formula of its oxide and chloride.

When Gallium (Ga) was discovered in 1875 by Paul Émile Lecoq de Boisbaudran, its properties remarkably matched Mendeleev's predictions for Eka-Aluminium. For instance, Mendeleev predicted Eka-Aluminium to have an atomic mass of about 68 and a density of approximately $5.9 \, \mathrm{g/cm^3}$. Gallium was found to have an atomic mass of $69.723$ and a density of $5.904 \, \mathrm{g/cm^3}$. This strong correlation between predicted and observed properties was a significant validation of Mendeleev's periodic law.

The incorrect option is (2): Scandium was predicted as Eka-Boron by Mendeleev, not Eka-Aluminium. It was discovered by Lars Fredrick Nilson in 1879.
The incorrect option is (3): Germanium was predicted as Eka-Silicon by Mendeleev, not Eka-Aluminium. It was discovered by Clemens Winkler in 1886.
The incorrect option is (4): Boron is a known element and was not a predicted element by Mendeleev using the "eka-" prefix. It is the element above aluminium in Group 13.