Answer:
1) synthesis MgI2
2) double replacement CuS + (HCl)2
3) double replacement, not sure ab the formula sorry
Explanation:
an acid will give away a proton and become a conjugate base.
A base will accept a proton and become a conjugate acid.
The periods inside the Periodic Table is B. a horizontal row, and is numbered 1 through 7
hope this helps