The empty cells predicted what the lab had not yet found.
4
elements predicted by the periodic table before their discovery
Eka-Boron
21
Sc
Scandium
Confirmed · 1879
Eka-Aluminum
31
Ga
Gallium
Confirmed · 1875
Eka-Silicon
32
Ge
Germanium
Confirmed · 1886
Eka-Manganese
43
Tc
Technetium
Confirmed · 1937