Atom R has a total of 58 elementary particles, in which the ratio of the number of neutrons to the mass number is 20/39. Give the number of particles of each type in R and the atomic symbol R?

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u.s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?