Diagnosing the Diagnostics

". . . but this agreement breaks down for radicals, complex molecules and homonuclear molecules. Using them interchangeably under such circumstances can lead in misleading description of nature and properties of the molecules . . . In lower level, students usually assume that compounds containing toxic elements like cadmium, mercury and lead are toxic too! In the same level, many believe that all metallic atoms are hard and all non metals are soft (Tsaparlis, 2002). On the other hand senior high school students and even university freshmen were found to have certain misconceptions on the difference between chemical and physical change (Jensen, 1998) . . .This implies that diagnostic tests like multiple choice items and two-tier tests are less efficient in exactly figuring out the extent of students' misconceptions. As a result such tests are not potential enough to discriminate misconception from lack of knowledge"