Gallium

1871
Dmitrii Ivanovich Mendelev predicts the existance and properties of the element
after zinc in the periodic table. He Gives it the name 'eka aluminium'.
1875
Paul Emile Lecoq de Boisbaudran discovers gallium.
Its properties closely match those predicted by Mendelev.
Gallium, atomic number 31, is very similar to aluminum in its chemical
properties. It does not dissolve in nitric acid because of the protective film of
gallium oxide that is formed over the surface by the action of the acid. Gallium
does however dissolve in other acids, and alkalies.
Gallium was discovered (1875) by…