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Asingle atom of an element has 21 neutrons, 20 electrons, and 20 protons. which element is it? ok o z

The missing component to the table to the right or indicated with orange letters complete the table by filling in the corresponding numbers or symbols

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.