Assuming the heterocyclic ring above to be planar: Give the number of electrons that are contributed to the pi system of the heterocyclic ring by:a. atom1 b. atom 2 c. atom 3 1) Enter NA for atom 3 if the structure above has only two numbered atoms 2) How many electrons are in the pi system of the heterocyclic ring? (In the case of fused rings add all the pi electrons.) 3) Is the heterocyclic ring with the numbered atoms aromatic?

15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.