Colder air is more dense than warmer air. Clouds can be formed that will lead to rain and thunderstorm formation along the cold front.
In your own words explain what occurs if cold air is more dense than warm air.

Ithink it’s one of those things that you put the object on

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.

D. h2o + h2o > h3o + oh- confirmed.

The ground state electron configuration of a phosphorous atom has  three unpaired electrons. they're in the 3p sublevel. the electron configuration is: , for a total of  15 electrons.