List the information you need to find how many milliliters of a stock solution of 2.00m mgso4 you would need to prepare 100.0 ml of 1.00m mgso4

We can use the dilution equation when preparing diluted solutions from concentrated solutions
c1v1 = c2v2
where c1 is concentration and v1 is volume of the concentrated solution
c2 is concentration and v2 is volume of the diluted solution prepared
substituting these values in the equation 
2.00 M x V = 1.00 M x 100.0 mL 
V = 50.0 mL 
50.0 mL of concentrated solution should be taken and filled up to 100.0 mL to prepare a 1.00 M solution