Question

In the 19th century, Dmitri Mendeleev predicted the existent of a then unknown element, X, with a mass of 68. He also predicted that an oxide of X would have the formula X2O3, on the modern period table. What is the group number and period of the element?

Answer 1

Gallium period 4..group 3(A)---it has similar property with Aluminium..so he called that element as eka-aluminium..(if im not mistaken...)