What is the chemical used in photographic films

well fixer is used for processing all commonly used films, including black-and-white films, Kodachrome, and chromogenic films, but in  chromogenic films, the remaining silver must be removed by a chemical mixture called a bleach fix, sometimes shortened to blix.

sure what is it? ^w^

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.