How many chemical bonds would you expect "ekasilicon" to form? and what atomic mass would you expect "ekasilicon" to have? why?

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

Decomposition is the cycle at which bacteria breaks down any organic material into the soil