Dr. Keith S. Taber
Publication:
Taber, K. S. (2003)
Understanding ionisation energy: physical, chemical and alternative
conceptions
Chemistry Education: Research and Practice, 4 (2), pp.149-169
Abstract:
There are many topics in chemistry where student performance in
formal assessments may be considered to largely depend upon the understanding
and application of concepts that may be un-problematically labelled 'chemical':
concepts such as 'element', 'neutralisation', 'addition reaction', etc. However,
there are also a number of curriculum topics from within chemistry where students
are required to be able to demonstrate and apply ideas which in themselves
may be seen as 'belonging' more to physics than chemistry. One such topic
is that of ionisation energy, where basic electrostatic principles must be
understood and applied. This paper discusses responses to a diagnostic instrument
on Ionisation Energy which highlight student difficulties appreciating conventional
physical principles. The instrument comprised 30 true-false items and was
administered to over 300 college level chemistry students in 17 institutions
in the UK. Respondents commonly agreed with statements reflecting previously
identified alternative conceptions relating to the 'sharing' of nuclear force,
and to the unconditional stability of species with full shells. The implications
of the findings for the teaching of chemistry are considered, with particular
reference to the debate about the extent to which chemistry can or should
be reduced to physics.