Question

Eka-boron was the name given by Mendeleev to the element similar to _______in properties:
(A) Scandium
(B) Silicon
(C) Aluminum
(D) Boron

Answer 1

The concept Eka-boron, Eka-aluminium was proposed by Mendeleev. Observe the options given carefully which may help us to come to a conclusion.

Complete step by step answer:
The periodic table was proposed by Dmitri Mandeleev which had regular periodicity but some places were left for unknown elements. He predicted the unknown elements by properties appropriately in order to fill the gaps in the periodic table. He named it Eka-Boron, Eka -Aluminum and Eka -silicon. The Eka -boron of atomic mass 44, the eka-aluminum of atomic mass 68 and eka-silicon of atomic mass 72. Some of the predicted elements were lighter than the rare earth metals; those elements are Eka- boron, Eka-aluminium, Eka-manganese and Eka-silicon etc. It proved him to be a good predictor.
Option A is scandium. The scandium oxide was isolated when its correspondence was recognized by Nilson. In actuality the scandium was found to have an atomic mass of 44.955. Mendeleev predicted Eka-boron of atomic mass 44 long back when it was isolated. So, we can say that Eka-boron is the scandium. Thus, option A is the correct answer.
Option B is aluminium. Mendeleev predicted Eka-aluminium long back. If he predicted means there was an unknown element which possessed the same properties as aluminum. This means aluminium was a known element. The Eka-aluminium is gallium. Thus, this option is the wrong answer.
Option C is Silicon. From the above we know that he predicted an unknown element Eka-silicon. This means silicon is before predicting these unknown elements. Thus, option C is the wrong answer.
Option D is Boron. This can be explained by the same explanation given to option B and C. Hence, option D is the wrong answer.

So the answer to this question is option A.**

Note: Just by knowing the elements which were predicted before predicting the unknown elements we can easily answer this question. Otherwise, just by knowing the names given by Mendeleev to the unknown elements that is Eka-Boron, Eka -Aluminum and Eka -silicon, this will help in answering the question within no time.