If you could drop 12 atoms of copper onto a beaker containing nitric acid, how many molecules of no would be produced?
a) 12
b)8
c)4
d)2

B) 8.0 molecules.

Explanation:

It is clear that 3.0 atoms of Cu react with 8.0 molecules of HNO₃ to produce 3.0 molecules of Cu(NO₃)₂, 2.0 molecules of NO, and 4.0 atoms of H₂O.

Note that: The no. of atoms and molecules is the same ratio to the no. of moles.

Using cross multiplication:

3.0 atoms of Cu produce → 2.0 molecules of NO, from the balanced equation.

12.0 atoms of Cu produce → ??? molecules of NO.

∴ The no. of molecules of NO produced = (2.0 molecules)(12.0 atoms)/(3.0 atoms) = 8.0 molecules.

it is stable as it is in group 0 which have full outer shells of electrons