Silver-plated utensils were popular before stainless
steel became widely used to make eating utensils. Silver
tarnishes when it comes in contact with hydrogen
sulfide, H2S, which is found in the air and
in some foods. However, stainless steel does not tarnish
comes in contact with hydrogen sulfide.
76 In the space in
your answer booklet, draw a Lewis electron-dot diagram
for the compound that tarnishes silver. 
77 In the ground state, an atom of which noble gas has
the same electron configuration as the sulfide ion in Ag2S?