As we start to study chemistry, our textbook presents many important ideas in a small number of pages - you may need extra help to understand these concepts. Freesciencelessons.co.uk has some good introductory chemistry lessons HERE. I strongly suggest you check out the videos on that page called
Each video is very short, about 4 minutes, so you could watch all four of those videos in about 16 minutes! You should watch the videos in order, so don't start with the one below, which is the one about electron energy levels. Warning: like your textbook, it tells a white lie about the third energy level, saying it can contain up to 8 electrons when in fact in can contain up to 18 electrons. If you don't believe me then ask Google "How many electrons can the third energy level contain?"
Freesciencelessons.co.uk has a video about the periodic table, and you can find another good one HERE. For other chemistry resources, see the resources page that I have made for the grade 10/11 chemistry class.