(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.
[3]
2. Calculate the percent composition of ammonium nitrate, NH4NO3
.
(Calculate the % by mass of each element in ammonium nitrate.)

Over the last 90 years, scientists have added to the body of evidence supporting the big bang theory. what is the latest piece of evidence discovered in 2014?

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

  the mississippians were considered to be  horticulturalists, which means they were