For the answer to the question above asking How many chemical bonds would you expect "eka-silicon" to form? I believe the answer is 4 chemical bond will "eka-silicon" form.
For the question, what atomic mass would you expect "eka-silicon"?
The answer is 72 (g/mol)
because, it's in between gallium and arsenic so if gallium's atomic mass is 70 and arsenic's atomic mass is 75, 72 is right between them
