A. 2
trust me i used to so this in middle school
Answer:
120.37 g
Explanation:
Mg = 24.31 g
S = 32.06 g
4 O = 16 X 4 = 64 g
Therefore, MgSO4 is (24.31 + 32.06 + 64) g = 120.37 g
Answer: The green copper (II) carbonate
changes to black copper oxide 

Explanation:
Decomposition is defined as the chemical reaction in which a single compound gives two or more simple substances. It requires energy to break the bonds between reactants, thus is an endothermic process.
Thermal decomposition uses heat for decomposition.
The chemical equation for thermal decomposition of copper (II) carbonate is:

The green copper (II) carbonate
changes to black copper oxide 
The question is: WHAT DATA OF THE ELECTRONIC CONFIGURATION ALLOWS YOU TO LOCATE THE CHEMICAL ELEMENTS IN THE PERIODIC TABLE?
Explanation:
Elements which have same number of valence electrons tend to show similar chemical properties due to which they are placed in the same group.
Hence, electronic configuration of an element tells us the number of valence electrons present in an element. As a result, it becomes easy to locate the element in its respective group.