Dificultades de comprensión de nociones relativas a la clasificación periódica de los elementos químicos: la opinión de profesores e investigadores en educación químic1

Thispaper analyzes thelearning difficultiesof students in secondary edu- cation about the subject of the Periodic Table of elements. We present the opinions of a sample of teachers in Chemistry and Science Education obtained from written questionnaires and semi-structured interviews. The information has been analyzed from a set of eight dimensions that allow us to systematize several sources of difficulty and different reasons that may hinder student learning in this subject. Specifically, we propose these dimensions: 1) attitudinal aspects, 2) memorizing 3) deficiencies about preconceptions in the lesson 4) misunderstanding of the properties used as criteria classification; 5) the notion of periodicity and the percep- tion of its usefulness 6) ambivalence of meanings of notions related with the Periodic Table; 7) the abstract nature of the concepts involvereasoning required; and 8) deficiencies in the teaching process.