Electronic configuration and position in periodic table https://docs.google.com/presentation/d/1kgM3hPdeL6efUtRQgCLkLOs1Xo_L6lye/edit?usp=sharing&ouid=103393407506730943424&rtpof=true&sd=true
https://docs.google.com/presentation/d/1w00VkG-DHsboJZSL5ioZQFEl9EMerzPK/edit?usp=sharing&ouid=103393407506730943424&rtpof=true&sd=true History of periodic table