End of the week and end of the semester

I’ve been teaching the second semester of sophomore organic this spring and we’re wrapping up the material in the next few classes. Many of the students are working hard and doing well, but I have the sense that, in general, student’s backgrounds are weaker. In particular, they are struggling with the basic concepts of Lewis structures and formal charges. I suspect that this is and effect of covid (nobody learned anything for two years) and that their earlier courses are increasingly based on rote learning.