A-level CHEMISTRY 7405/1 Paper 1 Inorganic and Physical Chemistry Mark scheme June 2021. 3.12 Organic structures Where students are asked to draw organic structures, unless a specific type is required in the question and stated in the mark scheme, these may be given as displayed, structural or skeletal formulas or a combination of all three as long as the result is unambiguous. In general • Displayed formulae must show all of the bonds and all of the atoms in the molecule, but need not s...