This research is aimsed to know improvement of chemistry learning outcomes of class X SMA on atomic structure TA 2017/2018 through the cooperative learning models type Number Head Together (NHT). This research is a class action research couducted in three cycles. Each cycle consists of four stages, numbering, questioning, head together ang answering. The subject of this research is all students of grade X SMA Darussalam Tangerang Selatan of 30 students. Data collection techniques in this research are using test and observations. Data analysis used is a qualitative descriptive analysis technique. The results of the research that the application of the cooperative learning type Number Heads Together (NHT) can improve the learning outcomes of students in class X SMA Darussalam Tangerang Selatan on atomic structure. Based on the results of the first cycle, the second sycle and the third cycle always increase. The average generated in the first cycle was 25,33 and then increased in the second cycle to 55,83 and increased again to 77,50 in the third cycle. The results of this class action research are the application of cooperative learning models type Number Head Together (NHT) to improve the learning outcomes of students in class X SMA Darussalam Tangerang Selatan on the atomic structure.

DOI: doi.org/10.24071/snfkip.2018.25