From your KLB Chemistry book 2 pgs 1-3 read on electronic arrangement and draw atomic structure of first twenty elements Students conduct the exercises.go to web links below and get more information
https://www.youtube.com/watch?v=6EI7Ii_Ye-4
https://www.youtube.com/watch?v=hZTYJrzb7FE
https://www.youtube.com/watch?v=tpwK57Tz0Ag