Introduction
Background of the study
No nation of the world will attain its zenith in technology or development without giving proper attention to the teaching and learning of science. The development of a nation depends largely on the level of scientific and technological advancement of that nation. Asiyai(2005) found that chemistry has helped in the development of modern technology through the application of its principles to modern inventions.The study of chemistry has been and will remain of tremendous importance to mankind because chemistry is capable of explaining natural phenomena and everyday occurrences.
Furthermore, Majekodunmi (2007) observed that chemistry has been contributing to the development and growth of Nigeria and the world at large. Chemistry has made food more abundant by improving agricultural production, provided improved clothing through chemically treated synthetic and natural fibres by making them resistant to stain, winkles and water. Chemistry gave us shelter and materials for building and repair. It also provided us with medicine for healthcare and fuel for transportation.
Despite the importance of chemistry in science and technological development, students‟ achievement in the subject at senior school certificate examination (SSCE) has been consistently poor. Appendix 1 shows trend of students‟ achievement from 1999 to 2010. The summary of chief examiners‟ reports by West African Examination Council (WAEC,2006) revealed that 39.8%,50.94% and 44.90% are percentage passes at credit level(grade1-6) in 2004, 2005 and 2006 respectively.(Appendix I). It also shows that students‟ achievement at credit level has not been good. It was only in 2005 that the percentage credit pass of the students was 50.94% and the lowest score was in 2002 when the students had 25.38%.
Asim, Bassey and Essien (2005) carried out trend analysis of West African Examination Council result from 1999 to 2003 and found that the achievement of the students over these years were generally poor. Appendix 1 also summarised the analysis of West African Examination Council result from 1999-2010 which confirms the findings of Asim, Bassey and Essien (2005).
Furthermore, Owokade (2007),analysed the West African Examination Council result from 2001 to 2005 and found that the cumulative pass rate at credit level in chemistry was 34.18%.The researchers have shown that there have been a downward trend in the achievement of secondary school students in chemistry over the years. (Bello 1990;Jimoh 2004; Njoku 2007; and Oloruntegbe and Omoifo 2008).
Also, the West African Examination Council Chief Examiners‟ report (2002, 2005 and 2007) revealed the following weakness of candidates in chemistry:
- Lack of knowledge of I.U.P.A.C system of naming
- Poor knowledge of symbols, formulae and equations
- Inadequate practical exposure
- Lack of understanding of nuclear chemistry
- Lack of understanding of basic concepts and principles which includes chemical bonding
- Inability to answer questions in electrolysis
- Lack of understanding of Redox reactions
- Poor knowledge of factors affecting rates of chemical reactions.
Chemical bonding as mentioned in number five above is in Senior Secondary one (SS1) revised Chemistry Curriculum.Chemical bonding is a central concept in the teaching of chemistry and therefore a thorough understanding of it is essential for understanding almost every other areas of chemistry, such as carbon compounds, proteins,polymers,acid and bases,chemical energy and thermodynamics .(Fensham,(1975),Gillespie(1997) and Hurst(2002).According to Gabel (1996), Robinson (2003) and Taber (2001),chemical bonding is considered by teachers, students and chemists to be a complicated concept. The concepts and structures such as covalent bond, molecules, ions, giant lattices and hydrogen bonds are abstract. In order to understand these concepts students must be made to be interested in the teaching and learning of the concept of chemical bonding. Franz and Harkerat (2010) reported that students have problem with understanding of chemical bonding. According to Franz and Harkerat(2010) knowledge in chemistry is based on students‟ understanding of basic principles.The traditional approach of using lecture method alone may not be adequate.
There is need to develop more effective and scientifically aligned strategies to teach senior secondary school one chemistry students the key concepts and principles of chemical bonding or else other topics mentioned before will not be understood if the student did not conceptualize the concept of chemical bonding. This can lead to poor achievement in chemistry. Bodner and Domin (1998) and Taber (2001) reported that students lacked a deep conceptual understanding of the key concepts regarding chemical bonding and how to integrate their mental models into a coherent conceptual framework. Levy, Hofstein, Mamlok and Bar-Dov (2004) found that student demonstrated a superficial understanding of chemical bonding not only because the concept has intrinsic complexities but the traditional teaching approach used alone for teaching the bonding is not effective. Thus, the need to consider an alternative approach to the teaching and learning of chemical bonding.
The students‟ inability to conceptualize chemical representation, especially the one involving transfer and sharing of electrons has been observed by the researcher for almost over twenty years of teaching chemistry in secondary schools. One wonders whether the use of alternative teaching approach like Animation Instructional Strategy (ANIS) may be a tool towards solving this problems. Ben, Eylon and Suberstein (1998) observed that chemical representation of symbols and molecules are not only difficult for students to understand, but are also abstract and cannot be understood by intuition.
