CHAPTER ONE 1.1       Introduction Chemistry as defined by Okeke and Ezekamgha(2000) as a branch of science that deals with composition and changes of matter. Chemistry is highly important for technological development and advancement of any nation. The number of chemists, physicists, doctors and science educators in a nation tells if the nation is developed, developing or underdeveloped. Chemistry is regarded as the “central science” because everything from our skin to the air we breathe is made up of atoms and this is what chemistry revolves around. This phrase (central science) was popularized in a textbook by Theodore. L. Brown and H. Eugen Lemay titled “chemistry; the central science” which was first published in 1977 with a Thirteenth edition published in 2014. Chemistry uses particles models to account for abstract constructs. Therefore, chemical processes such as melting, evaporation, dissolving, diffusion, electron transfer, ion conductor, intermolecular bond and many others are fundamental to learning of chemistry in schools and colleges. A concept is defined as a “perceived regularity in objects or events” Or a record of events designed to be labeled. Typically, a concept is expressed using 1  one or just a few words, one of which is a noun. Examples; Kinetic energy, thermodynamics e.t.c. Further explanation will be discussed on the study and how chemistry concepts affect academic achievements of students in senior secondary school. In the current study, effort would be made to identify the concepts that are difficult to students in chemistry so that the need to offer them a special treatment by science educators will be pointed out. 1.2       Background of the Study. Background of this study is to identify the inherent factors and concepts that affect the achievement of students in chemistry. Such factors include; student’s misconception and preconception in chemistry, difficult and alternative conception in chemistry, difficulties with abstract concepts, conceptual changes method at college level. Academic achievement of chemistry students and influence of study habits, psychological factors on academic achievement. 1.3       Statement of the Problem This study intends to make known the various abstract concepts in chemistry and how they affect the academic achievement of students in senior secondary schools. It also stresses the abstract and highly conceptual nature of chemistry 2  which makes students perceive chemistry as a difficult subject. The study will also look into the general slow pace of the effects and affective characteristic of students and the academic achievement in chemistry and how it’s likely to affect the production of teaching profession competency in chemistry. 1.4       Purpose of the Study The general purpose of this study is to identify difficult concepts in chemistry and their effects on the academic achievement of students’ in secondary schools in Sokoto metropolis. This purpose is further down into the following objective for the study: Ø  To explore the concepts in chemistry which students perceived as difficult, Ø  To investigate into the students conceptual difficult and how it affect their academic achievements. Ø  To examine whether or not the difficult concepts perceived by students influence the students interest towards the study of chemistry and Ø  To investigate whether or not the students’ gender differences have significant influence on their perception of difficult concepts in chemistry. 3  1.5       Significance of the Study Over a number of years, many of the difficult areas in chemistry were subjected to systematic study to identify the point of difficult and to seek common factors among the nature of these difficulties. The present study however generates data on come concepts perceived as difficult in chemistry and their effect on academic achievements of students. The study also generates information on whether or not the difficult concepts perceived by students improved their achievements and ability to solve higher order question in chemistry. Curriculum designed will utilize this information to enrich the curriculum for teachers’ preparation at secondary level of our educational system. 1.6       Research Questions The following research questions were raised in the study Ø  What concepts in chemistry do students in this study perceived difficult? Ø  Do the concepts perceive difficult influence the academic achievement of the students?