Why do groups among the among the main group elements display similar chemical behavior

Air can be considered a mixture. which statement does not explain why?

0.88 moles of n2o5 (g) was placed in a sealed 1.00 l vessel. calculate the equilibrium concentration of n2o5. no2, and o2 and the equilibrium constant after equilibrium has been reached by 65.0% of the n2o5 decomposing.

Idid a lab for chemistry where we put nails in a copper (ii) chloride solution. 1. why did the reaction stop? which reactant was used up? how do you know? 2. describe what was happening to the atoms of iron and copper during the reaction. what is this type of reaction called? 3. what would happen to the ratio of copper to iron if you had placed more nails in the beaker? if you had let the reaction go for less time? 4. what is the accepted ratio of copper atoms to iron atoms in this reaction? account for differences between your experimental value and the accepted value. write the balanced equation for the reaction.