A standard temperature and pressure a 0.5 mol sample of h2 gas and a separate 1.0 mil sample of O2 has have the same

8.7 degrees celsius and 15.6 degrees fahrenheit

Particle exchange energy though elastic collision , hope this .

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.

Less stable  hope this