which of the following is the correct formula for magnesium nitrate?

The correct formula for magnesium nitrate is Mg(NO₃)₂.

Quick explanation

• Magnesium forms a Mg2+Mg^{2+}Mg2+ ion, carrying a 2+ charge.

• Nitrate is the polyatomic ion NO3−NO_3^{-}NO3−​, carrying a 1− charge.

• Two nitrate ions are needed to balance the 2+ charge of one magnesium ion, giving the neutral ionic compound Mg(NO₃)₂.

So, if the options look like:

• MgNO₃
• Mg₂NO₃
• Mg(NO₃)₂
• Mg₂(NO₃)₃

the correct choice is Mg(NO₃)₂.