Mediating mental models of metals: Acknowledging the priority of the learner's prior learning

Abstract

This paper describes the conceptualizations, or mental models, of the nature of the bonding and structure of metals of a group of U.K. college students. It is suggested that these mental models may be understood in terms of the students' prior learning about covalent and ionic bonding, and the prevalence of a common alternative conceptual framework for chemical bonding labeled "the octet framework." This study illustrates the prominence of prior learning in channeling the interpretation of subsequent teaching, and highlights the significance of the decisions made by curriculum planners, textbook authors, and teachers on the order of presenting subject content, the degree of simplification of scientific models, and the selection and presentation of metaphors.

Effects of Cooperative Learning on Students’ Understanding of Metallic Bonding

“…The similar misconceptions were revealed also in the research of Taber (2003), which indicated that students thought metals had a few covalent bonds and mainly ionic and weak van der Waals forces. As mentioned by De Posada (1997), students commonly had misunderstandings and misconceptions related to the constitution of electric current in metals.…”

“…Students also explained that there was no bonding in pure metals or there was just a force and not a real chemical bond (Table 1). In her other study, Taber (2003) asked students to describe and explain the bonding in metals to examine their conceptualisations, mental models related to the nature of the bonding and structure of metals, and they found that students had some difficulties and insufficient models as in the previous study.…”

“…As the light does not pass through metals, I suppose that the molecules must be very close to one another (De Posada 1997) The charged species in metallic lattices are nuclei rather than ions (Coll and Taylor 2001) Metallic lattices contain neutral atoms (Coll and Taylor 2001) Confusion over metallic bonding and other chemical bonds Molecular iodine is metallic in nature (Coll and Taylor 2001) Continuous metallic lattices are molecular in nature (Coll and Taylor 2001;Taber 2001) The bonding in metals and ionic compounds involves intermolecular bonding (Coll and Taylor 2001) Ionic and metallic bonding contain an element of directionality (Coll and Taylor 2001) Metal to non-metal bonding in alloys is electrostatic in nature (Coll and Taylor 2001) Metals have covalent and/or ionic bonding (Taber 2001) Metals are good conductors because they contain only a few co-valent bonds, mainly Ionic and Van der Waals (Taber 2003) In metal the electron are covalently bonded (Taber 2003) If an atom has, six electrons in outer shield, it would share two extra electrons from another substance to make it up to an eight (Taber 2003) Because iron metal has two-plus, the bonding in iron is ionic (Taber 2003) Metals have bonding similar to ionic because there is positive and negatives (Taber 2003) Nature of metallic bonds There is no bonding in pure metals (Taber 2001) There is just a force and not a real chemical bond in metals (Taber 2001) There is some form of bonding in metals, but no proper bonding (Taber 2001) All the iron atoms are same and don't need to be bonded (Taber 2003) Because they are the same sort, they hold together (Taber 2003) bonding; (3) metals have covalent and/or ionic bonding; (4) metals have metallic bonding. For many of these students, chemical bonding was understood in term of striving to obtain a full outer shell by sharing (covalent bonding) or transferring (ionic bonding) electrons.…”

Learning quanta: Barriers to stimulating transitions in student understanding of orbital ideas

“…Ausubel considered prior knowledge to be the most significant factor in planning teaching, and the constructivist perspective acknowledges how the learners' existing conceptual frameworks are the resources for "making sense" of new information (e.g., Driver, 1989;Fensham et al, 1994), such that prior learning can "take priority" over the teacher's message (Taber, 2003b). Teachers are advised that teaching should therefore be planned in the light of a conceptual analysis of the topic to be taught (Heron et al, 1977), to determine the necessary prerequisite knowledge, as well the optimum order of presentation of material, etc.…”

Students' progression of understanding the matter concept from elementary to high school

“…This large body of knowledge revealed students' alternative conceptions on the following major aspects of the matter concept: conservation (BouJaoude, 1991;Stavy, 1990;Watson, Prieto, & Dillon, 1995), composition and structure (Benson, Wittrock, & Baur, 1993;Coll & Treagust, 2003;Doran, 1972;Griffiths & Preston, 1992;Krnel, Glazer, & Watson, 2003;Krnel, Watson, & Glazar , 1998;Novick & Nussbaum, 1978, 1981Nussbaum, 1985;Peterson, Treagust, & Garnett, 1989;Stavy, 1991;Taber, 2003), physical properties and change (Haidar & Abraham, 1991;Krnel, Watson, & Glazar, 1998;Lee et al, 1993;Osborne & Cosgrove, 1983;Shepherd & Renner, 1982), and chemical properties and change (Boo & Watson, 2001;BouJaoude, 1991;Hesse & Anderson, 1992;Johnson, 2000Johnson, , 2002Nieswandt, 2001;Solomonidou & Stavridou, 2000;Stavridou & Solomonidou, 1989Voelker, 1975;Watson, Prieto, & Dillon, 1995). This large body of knowledge covers grade levels from elementary to university and diverse cultural backgrounds.…”