(2008? Xining) (1) It is reported that the rocket power for carrying Chang 'e-1 satellite is provided by the decomposition of ammonium perchlorate (chemical formula: NH4ClO4).

(1)① According to the chemical equation, the reactant contains: 2 nitrogen atoms, 8 hydrogen atoms, 2 chlorine atoms and 8 oxygen atoms; There are two nitrogen atoms, two chlorine atoms and four oxygen atoms in the product. Comparing the number and types of atoms before and after the reaction, we can know that the product still lacks 8 hydrogen atoms and 4 oxygen atoms, and because the number before X is 4, the chemical formula X contains 2 hydrogen atoms and 1 oxygen atoms, so the chemical formula is H2O；; ;

② The number in the lower right corner of the chemical symbol indicates the number of atoms contained in a particle, and the "2" in the lower right corner of N2 indicates that a nitrogen molecule consists of two nitrogen atoms; The number in front of the chemical symbol indicates the number of particles, so the "2" to the left of 2O2 indicates two oxygen molecules;

(2) From the information in the label, we can know that mineral water contains eight elements such as Na, Ca, K, H, C, O, Cl and S, and the particles in the label are all charged, so the chemical symbol in the table is ion.

So the answer is: (1) ① H2O; Law of conservation of mass (or the species and quantity of atoms remain unchanged before and after chemical reaction);

② A nitrogen molecule consists of two nitrogen atoms; ② oxygen molecules;

(2)8; ion