Question

what type of oxide would Eka-Aluminium form and how ???​

Answer 1

eca aluminium is also called as gallium

Answer 2

Explanation: Eka Aluminium is the element after aluminium and is named as gallium. As they both belong to same group the valency of gallium will be same as aluminium and will be 3.
It can lose three electrons to attain nearest noble gas configuration.Thus valency is 3.
To form a neutral oxide with O2- , eka aluminium must form a compound E2O3