13. (07.06 LC) Which of the following is true for the equilibrium constant of a reaction? (4 points)
It is a ratio of coefficients of reactants to products.
It has a different value at different temperatures.
It is represented by the symbol H.
Its value is always less than 1.

And a) oxygen i believe

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.