Alternative Conceptions of Chemical Bonding Held by Upper Secondary and Tertiary Students

Examination of senior secondary and tertiary level chemistry students' descriptions of their mental models for chemical bonding revealed prevalent alternative conceptions. In addition to some common alternative conceptions previously reported in the literature, such as misunderstandings about intermolecular forces and molecularity of continuous lattices, the inquiry found a surprising number of alternative conceptions about simple ideas like ion size and shape. Some 20 alternative conceptions were revealed, the most common being belief that continuous ionic or metallic lattices were molecular in nature, and confusion over ionic size and charge. It is posited that the mass of curriculum material students encounter during their undergraduate and postgraduate studies may have some influence on the formation of alternative conceptions. Hence, it is recommended that tertiary level teachers in particular consider the advisability of limiting the teaching of some abstract models for chemical bonding until an advanced stage of the undergraduate degree.