Principal shell shows the main energy level, in that there are some more energy levels. This is how the atomic structure is defined according to the Quantum Mechanical model of atom. So exactly why do subshells exist and all i don't know
The relative formua for Potassium bromide is Kbr
14. C
15. B
16. D
17. D
18. I am not sure sorry.<span />
Light is helpful because it allows us to see things around us.
I hope this helps :)
