Please help me! What are the molarities?

What elements have 2 electrons inthe 4s sublevel

How would the number of moles (n) of o2 change if the atmospheric pressure doubled but all other variables stayed the same

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.