8. Calculate the density of a substance with a unit cell volume of 1.95 x 10^6 pm3 and a unit cell mass
of 2.5 x 10^-22 g.

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.

Ibelieve the answer is weathering,hope my answer has you : ) 

Atp, shorthand for adenosine triphosphate, is the standard molecule for cellular enger in the human body. all motion and metabolic  processes  within the body begins with energy that is released from  atp, as its phosphate bonds are broken in cells through a  process  called hydrolysis.

Seems cool i guess ttyl