CHM-2023-CG3-086

Consider the following compounds/species (figure-dependent: i. naphthalene, ii. cyclopentadienyl anion (5-membered ring with lone pair, negative charge), iii. cyclobutadiene (4-membered ring), iv. cyclopropenyl anion (3-membered ring with lone pair, negative charge), v. cyclopropenyl cation (3-membered ring, positive charge), vi. cyclooctatetraene (8-membered ring), vii. anthracene — not transcribable as text). The number of compounds/species which obey Huckel's rule is