Substance appearance melting point (oc) electrical conductivity reaction with hcl a black powder 3500o c none no reaction b reddish pellet 1360o c high no reaction c shiny silver strip 1200o c high vigorous bubbling d dull gray pellet 620o c high very slow bubbling in a lab experiment, students had four samples of elements. they made observations about the appearance of each sample, then proceeded to conduct three separate experiments. in the first, they found the melting point of each by holding small samples in a bunsen burner with a temperature probe. in the second, they held a conductivity probe to two separate sections of the sample. in the final test, they reacted a small sample with hydrochloric acid and noted the results. which of these elements is most likely to be magnesium, the most metallic of all the samples?