Students took notes from the Lesson 9 PowerPoint, learning about the concepts of atomic mass, protons, and neutrons, and isotopes. Students also learned about electrons and the concept of electronegativity. They then worked together in groups of four to complete the Lesson 9 Worksheet. For homework, students were instructed to complete the worksheet, answer questions 1 and 2 from the end of Lesson 9 in the textbook, and then to read Chapter 10 in the textbook. Notes from the whiteboard are pictured below.