For the element Praseodymium, which has 59 electrons, what is the electron configuration? 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f3

1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 3

1s4 2s4 2p6 3s4 3p6 3d10 4s4 4p6 4d10 4f6

1s 4 2s 4 2p 6 3s 4 3p 6 3d 10 4s 4 4p 6 4d 10 4f 6

1s1 2s1 2p3 3s1 3p3 4s1 3d5 4p3 5s1 4d5 5p3 6s1 4f7 5d5 6p3 5f7 7s1 5f7 6d3

1s 1 2s 1 2p 3 3s 1 3p 3 4s 1 3d 5 4p 3 5s 1 4d 5 5p 3 6s 1 4f 7 5d 5 6p 3 5f 7 7s 1 5f 7 6d 3

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f3 5s2 5p6

Which is a chemical property of iron? a. it forms iron oxide (rust) when exposed to moisture and air. b. it is a gray–black metal that is hard to the touch. c. it has a melting point of 2795°f (1536°c). d. it is a good conductor of heat

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.

Areaction in which products can react to re-form reactants is