Changing ideas about the periodic table of elements and students' alternative concepts of isotopes and allotropes

Abstract

The Periodic Table of Elements (PTE) is one of the organizing principles in chemistry. Originally it was a list of elements (as substances). Later, the PTE developed into a list of atoms of the elements. However, isotopes and allotropes are difficult to integrate into the PTE. Therefore, difficulties in understanding these terms can be expected. The investigation set off to study secondary school students' concepts of isotopes and allotropes and how the concepts are linked to the PTE. Three specific research questions were addressed: (a) How do secondary school students describe the relationship between fundamental particles constituting an atom? (b) How do they conceive isotopes? and (c) What are students' concepts of graphite and diamond? Multiple choice items were given to 3074 senior high school students. In addition, six interviews were conducted with senior high school students. The data analysis revealed students' alternative concepts, which distinguished between standard atoms and atoms of isotopes. Standard atoms contain neutrons and protons in equal numbers and are more stable. The atomic masses are expressed as integers. Moreover, students considered graphite and diamond as isotopes. The analysis of the results shows that students actively tried to make sense of what they had experienced.

A reconstruction of development of the periodic table based on history and philosophy of science and its implications for general chemistry textbooks

“…It facilitates a succinct organization and understanding of the fundamental building blocks of chemistry, the chemical elements (Atkins, 1995). Research in chemistry education continues to emphasize the importance of the periodic table for learning chemistry (Akeroyd, 1991;Ben-Zvi & Genut, 1998;Bouma, 1989;Campbell, 1989;Giunta, 1998;Goh & Chia, 1989;Laing, 1989;Marshall, 2000;Rayner-Canham, 2000;Robinson, 2000;Scerri, 1998;Schmidt, Baumgärtner, & Eybe, 2003;Treptow, 1994). According to one historian of chemistry: ''From the 1870s Mendeleev's Periodic Table came to adorn every chemical lecture room; it compressed a great deal of knowledge into a small compass, meaning that the student no longer had to be burdened with a great load of unrelated brute facts'' (Knight, 1998, p. xii).…”

Examination of the preservice chemistry teachers’ understanding of periodic table concepts

“…However, in time, it became a complex table of many different chemical and physical properties of the elements (such as melting point, boiling point, chemical bonding, atomic radius, ionization energy, intermolecular forces isotopes and allotropes). For this reason, it is expected that there will be difficulties in understanding of these concepts [10]. Some studies available in the literature report that the main problem students trying to learn chemistry have is students' failure to learn the basic concepts [12,13,14].…”

“…Periodic table, one of the basic subjects of chemistry, plays important roles in understanding chemical elements [7]. Several studies have emphasized the importance of periodic table [7,8,9,10].…”

Understanding the Idea of Chemical Elements and Their Periodic Classification in Spanish Students Aged 16–18 Years

“…The concept of chemical elements, their properties and the law of periodicity are amongst the topics that are now considered as cornerstones both in history (Schmidt, Baumgärtner & Eybe, 2003;Scerri, 2007Scerri, , 2011Esteban, 2009) and the teaching of chemistry (Ben-Zvi & Gemut, 1998;Demircioğlua, Demircioğlua & Çalikb, 2009). This situation means that this topic is one of the most frequently discussed in chemical education publications, as evidenced by a review of articles published in journals such as The Journal of Chemical Education (Linares, 2004;Linares & Izquierdo, 2007).…”