Question

Electron configuration?

This is the electron configuration of `U_{92}` I found in a book. What do they want to say by using "/"?

Answer 1

See carefully they are indicating where a period in the Periodic table ends and how many elements are there in that period

Explanation:

before first"/" there are two electron which means there are total no. two elements in that period.
similarly in second and third "/" it shows that this period has 8 elements..........like this it goes on to the group and period where`U_92` is located there it has `7s^2 6d^1 5f^2`
as it says it is in 7th period and third group(we are not adding the f electrons as they (f- block) belong to the same group)