The smallest unit that can exist as an element and still have proprieties of that element is an Atom<span />
The main <span>hazard </span>is the Radiation and the Gamma rays that are dispersed
Explanation :
The balanced chemical reaction will be,

By the stiochiometry, 3 moles of solid copper(II)oxide react with 2 moles of ammonia gas to give 3 moles of copper metal, 1 mole of nitrogen gas and 3 moles of liquid water.
The states of matter of each elements and compound is,
Copper(II)oxide is in solid state
Ammonia is in gaseous state
Copper metal is in solid state
Nitrogen is in gaseous state
Water is in liquid state
6CO2 + 6H2O → C6H12O6 + 6O2
glucose produced = 1/6 x 23.6 = 3.93 moles