Answer:In regards to writing the formula, we know that magnesium has a charge of 1+ and sulfate, SO4, has a charge of 1-. Sulfate is a polyatomic ion so the charge of the whole thing is (SO4)1-. When you combine them you end up with MgSO4 and the "heptahydrate" is seven water molecules.
Explanation:
F because it NEVER forms any cations in chemical reactions
Ice, water, fog/water vapor
The trajectory of their motion knocked the Earth into a different orbit.
