(c)Magnesium nitride is also an ionic compound. Draw a dot-and-cross diagram which shows its formula, the charges on the ions and the arrangement of the valence
electrons around the negative ion.
Use x to represent an electron from a magnesium atom.
Use o to represent an electron from a nitrogen atom.

2. Calculate the percent composition of ammonium nitrate, NH4NO3
.
(Calculate the % by mass of each element in ammonium nitrate.)

The formula is (nh4)2co3

1) according to the law of conservation of mass ,in all chemical reactions total mass is unchanged

Answerthis solution will not form a precipitateexplanationsolubility equilbrium:         pbf₂(s)  ⇄ pb²⁺(aq) + 2 f⁻(aq)the solubility product expression is    (we exclude solids from the equilibrium expression).now suppose we have the trial ion product q, which we can define as    then, we can interpret  q as the product of the concentration of the ions that we have and ksp as the product of the ion concentrations that are needed to form a saturated solution.if q > ksp, then that implies that there will be a surplus of ions that exceed the amount that is required to form a saturated solution. a precipitate will then form (the precipitate continually  forms until the surplus ions are removed and q is decreased to ksp's value).if q = ksp, the saturated solution that forms is barely saturated and the precipitate will be minimal.if q < ksp, then the ion concentration will not be enough to form a saturated solution (so no precipitate).using our information, we calculate the trial ion product:     since q = 2.7  × 10⁻⁸ < ksp =  4  ×  10⁻⁸, a precipitate will not form.