ABSTRACT

The study was conducted to identify students? levels of conceptions of three-dimensional (3-D) organic molecular structures in Chemistry, in senior secondary schools (SS III) in Agbani education zone of Enugu State. Three research questions and two null hypotheses guided the study. Descriptive survey research design was employed for the study. The population for the study was 660 students comprising of 341 males and 319 females. Multi-stage sampling techniques were used to sample 310 respondents. The instrument for data collection was a diagnostic test to identify students? levels of conceptions (DTISLC) in 3-D organic molecular structures. To ensure the validity of the instruments, the instruments were face validated by two expert from Chemistry Education and two experts from Measurement and Evaluation, all in Department of Science Education, University of Nigeria Nsukka. The data generated from the trial testing was analyzed using Kindal coefficient of concordance, and the reliability index of 0.91 was obtained. Frequency and percentages were used to answer research questions, while Chi-square was used to test the null hypothesis at 0.05 level of significance. Findings of the study showed that many students have partial conceptions of IUPAC nomenclature of branched or substituted 3-D organic molecular structures in chemistry. Many students also have correct conceptions of numbering of unbranched parent carbon chain, drawing of structures of simple unsubstituted molecules and differentiating between isomers and transformation of formulas. The study also found that gender has no significant influence on students? levels of conceptions in four groups (1, 2,5and 6) out the six groups under which the concepts were discussed. The influence of school location is significant only in one group
(3) out of the six groups.

CHAPTER ONE
INTRODUCTION
Background to the Study
In Nigeria education system, science is so important that it?s teaching and learning has been greatly emphasized. Chemistry is one of the most important branches of science; which enables learners to understand what happens around them. Chemistry is a core subject for Medical Sciences, Textile Science, Agricultural Science, Synthetic industry, printing technology, Pharmacy, Chemical technology etc (Jegede, 2007). Chemistry is one of the science subjects in science curriculum that is important for any given progress in technology. It occupies a central position among all sciences (Ahiakwo, 2012). The current West African School Certificate Examination (WASCE) and National Examination Council (NECO) syllabus in chemistry contains topics in physical, inorganic, analytical and organic chemistry which is the basic focus of this study.
Organic chemistry is an essential part of everyday life and it has enormous economic importance in breweries, cosmetic industry, plastic etc. Chemistry learning requires much intellectual thought and discernment because it is replete with many abstract concepts (dissolution, particulate nature of matter, bonding and structures etc.) which are central to further learning in both chemistry and other sciences (Taber, 2002). These abstract concepts are important because further studies in chemistry concepts or theories cannot be easily understood if these underpinning concepts are not sufficiently grasped by students (Coll & reagust, 2001; Nicoll, 2001). One of the essential characteristics of concept learning in chemistry is the constant interplay between the three levels of thought (macroscopic, microscopic and symbolic levels). In organic chemistry, the symbolic level which involves formulas, structures and equations etc is a major challenge to students (Sirhan, 2007).