If a 14.3 cm3 sample of lake water is found to have 177.5 ng as, what is the concentration of arsenic in the sample in parts per billion (ppb), assuming that the density of the lake water is 1.00 g/cm3?

1) how many electrons are in each energy level of the following elements? a. he b. na c. na d. ne 2) how many valence electrons are percent in the following atoms? a. s b. mg c. be d. cl 3) which of the following elements are stable as atoms? a. he b. o c. cl d. ar if you are able to provide the work as to how you got the answers that would be greatly appreciated. : )

The reaction q+r2=r2q is found to be first order in r2 and

Which of the following units is not an official si unit? mole liter kilogram ampere