https://excalidraw.com/#json=gsZHB0QTOmJ1zFWhSgIGH,8MG4lvaaRIMdW5G8ytukgg
You can practice on Khan Academy before any test:
Copyright:https://www.slideserve.com/tessai/shells-and-subshells-powerpoint-ppt-presentation
https://www.youtube.com/watch?v=UDmrRWeFWwU
Best video for the lithium ion battery:
Very visual, like 100% better to learn with this.