melissa- HELP!!!

the radius of a chlorine atom is 99 pm and its mass is 5.89 X 10^-23 grams what is the density When I look at this i know that 99pm= 9.9e-7 and to get volume v=(3/4) or 1.33 (3/4)*3.14- pi *r^3 When I get to this point I do: 1.33*3.14= 4.1762*9.9e-7= 4.1e...