The colourless coating on a photographic film contains a chemical substance which reacts upon exposure to light, causing the film to darken. Which of the following substances is present in the darkened parts of the film? A. Bromine

C. Silver

B. Carbon

D. Silver bromide

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.