When a certain nuclide undergoes alpha emission, astatine-217 is produced. What is the identity of the nuclide that underwent decay? a. actinium-219
b. francium-217
c. francium-221
d. astatine-221
e. actinium-221
Please explain the answer

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.

What is the common name for the compound shown here? enter the common name of the compound shown?

Which of the following is a physical change? a.burning a piece of wood b.sawing a piece of wood in half c.rust forming on an iron fence d.a copper roof changing color from orange to green