Which element has the same number of energy levels as aluminum (al) and the same number of valence electrons as calcium (ca)? a. beryllium b. sodium c. potassium d. magnesium

In the following redox reaction which is the oxidizing agent and which is the reducing agent? alcl3 + na nacl + al oxidizing agent = reducing agent =

Which element has the lowest electronegativity? calcium(ca) gallium(ga) selenium(se) bromine(br)

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.