Which is the correct lewis structure for carbononitridic chloride (cncl)? a b c d

Which of these conditions most likely produces an unstable isotope?

Can someone me with 3 and 4 plz. this is for masteries test.

16. in a reaction that has reached equilibrium, a. the forward and reverse reactions are occurring at the same rate. b. the reactants and products are in equal concentrations. c. the forward reaction has gone further than the reverse reaction. d. there are equal numbers of atoms on both sides of the equation. e. a, b, and d are correct.