Investigation And Study On The Learning Level Of Middle School Students' Atomic Structure Concept

The content of atomic structure and properties occupies an important position in the study of chemistry throughout the middle school.It is an important content to be studied in junior high school,compulsory and elective stages,and it is continuously deepening in depth and breadth.The concepts related to atomic structure are not only abstract,but also become more and more complicated as the depth deepens.Therefore,students often show a series of difficulties in understanding these concepts.Explore students' understanding of the concept of atomic structure,understand the difficulties of students in understanding related concepts of atomic structure,clarify the disparity of concepts,and take effective strategies to improve the understanding of atomic structure concepts.The content of the atomic structure of students and the effect of chemistry learning are of great significance.The research conducted a systematic and in-depth analysis of the development history of curriculum standards,textbooks,and atomic structure models.A conceptual diagram of the concepts related to atomic structure was drawn.Based on the development of atomic structure models,the study of atomic structure-related content was combined with curriculum standards and textbooks' requirements,an advanced theoretical model for the development of the understanding level of atomic structure concepts was constructed,and the concept understanding was divided into three levels.Based on the theoretical framework,through a variety of ways such as consulting literature,consulting front-line teachers,and interviewing students,the in-depth understanding of the common alternative conception of students in the understanding of atomic structure-related concepts,based on the Rasch model combined with the alternative conception performance of students develop investigation tools to conductempirical research on advanced theoretical models for the development of understanding of atomic structure concepts,and effectively measure the types of heterogeneous vision in students of different ability levels,and analyze students' The process of understanding the concept of atomic structure.A total of 341 valid samples(including junior high and high schools)were selected,and the testing tools were revised after prediction,and a high-reliability and valid atomic structure concept understanding level testing tool was obtained.The study further selected a total of1,149 middle school students from 7 junior and senior high schools,and conducted a formal survey.Based on empirical data,we find that the advanced model for the development of the understanding level of atomic structure concepts constructed in this study is ideal.Level 1 : knowing that atoms are composed of nuclei and electrons outside the nucleus;the relationship between the number of atoms constituting particles affects the type and nature of the atom;knowing the influence of the interaction force between atoms on the atom,which mainly reflects the Rutherford model;Level 2:preliminary understanding of the arrangement of extra-nuclear electrons on the energy layer;ability to analyze element properties from the perspective of intra-atomic interaction(interaction between the nucleus and the energy layer),which mainly reflects the typical understanding of the Bohr model;Level 3:be able to analyze element properties from the perspective of intra-atomic interaction forces(the interaction of the nucleus with the energy layer and energy levels);know the fluctuation of the state of motion of electrons outside the nucleus;A typical understanding of quantum mechanical models.We analyze the changes of students' alternative conception of different ability levels,and find that students have four typical manifestations of the understanding process of atomic structure concepts:(1)With the improvement of students' ability,the students' alternative conception thoughts are constantly decreasing.This it is themost ideal transformation of disparity;(2)During the formation of complex concepts,students will appear as U-shaped curves as part of the ability level increases,indicating that with the study of scientific concepts,some the holding probability of some alternative conception..For example,the electron layer is the trajectory of electron movement;the electrons move around the nucleus in different orbits;the electrons make high-speed circular motion outside the atomic nucleus;the Bohr model;the Rutherford nuclear model,the atomic chemistry of isotopes are different.;the maximum number of electrons in the outer layer is 8,;the energy of the electrons in the same energy layer is the same;the greater the energy level,the farther the average distance of the electrons from the nucleus;The n-th electron layer contains n energy levels.A total of 10 isomerized transformation processes;(3)Some alternative conception want to remain relatively unchanged in a large capacity span,that is,with the improvement of the student's ability level,the alternative conception do not change,which shows that partial alternative conception is very difficult to transform.For example,the electrons make high-speed circular motion outside the atomic nucleus;Rutherford nuclear model,;the electron energy is continuous;the low-energy electrons are first discharged into the inner layer.;The amount of energy absorbed in the transformation;the electron spin direction is clockwise and counterclockwise,a total of 8 phase isomerization transformations;(4)The type of alternative conception of students with different ability levels has changed,indicating that the transformation of partial alternative conception may not be directly converted into scientific concepts,but in the process of transformation,other alternative conception are considered as a springboard.This situation occurs in the formation of the four concepts of atomic structure model,extra-nuclear electron arrangement,energy layer,and atomic orbit.We further analyze the alternative conception of students with different ability levels,and summarize the typical alternative conception about the "atomic structure" of students of different levels.The analysis found that some alternative conception disappeared with the improvement of students' ability level,which indicates that this part of the alternative conception is transformed into scientific concepts as the learning process continues to deepen.Some alternative conception still exist even in students who have a high level of understanding of atomic structure concepts.We call them resultive alternative conception.This kind of alternative conception is difficult to transform in teaching.We must pay special attention to these.Finally,we summarize the enlightenment of the research and reflect on the deficiencies of the research.