Ions and ionisation energy

Abstract

Previous research (Taber, 1999, 2000a) has shown that A-level students in the United Kingdom had difficulty understanding the concepts involved in ionisation energy. The purpose of this study, which involved the use of interviews and written instruments, was to determine if Grades 11 and 12 students (16 to 19 years old) in Singapore had similar alternative conceptions and explanatory principles of the factors influencing ionisation energy as their A-level counterparts in the United Kingdom (U.K.), as well as to explore students' conceptions of the trend of ionisation energy across different elements in the Periodic Table. The results showed that many students in Singapore applied the same octet rule framework and conservation of force thinking to explain the factors influencing ionisation energy as students in the U.K. In addition, the students resorted to relation-based reasoning to explain the trend of ionisation energy across period 3 elements. The authors believed that the way ionisation energy was taught.and presented in textbooks could be the cause of students' difficulties in understanding ionisation energy. Teachers and textbooks need to focus explicitly on the effects of nuclear charge, the distance of the electron from the nucleus, the repulsion/screening effect of the other electrons present, and the interplay between these factors to explain the factors influencing ionisation energy and the trend in ionisation energy across period 3.