modelling- why do mathematicians simplify their models and what needs to be taken into account in models (specifically conditions)

added new chem cards on atomic mass and fixed up some from yesterday which were accidentally in a folder for the theory part of driving

today I added the basic formulas covered in the aqa specification of pure a level maths :)

today I filled in the gaps that I didnt know before about electrostatic repulsion and what atomic numbers are responsible for in the basics of OCR A-level chemistry. :)