1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵
Here's how to understand this:
* 1s²: The first energy level (n=1) has one sublevel (s) with two electrons.
* 2s² 2p⁶: The second energy level (n=2) has two sublevels (s and p) with a total of eight electrons.
* 3s² 3p⁶ 4s² 3d¹⁰ 4p⁵: The third and fourth energy levels (n=3 and n=4) have a total of 35 electrons distributed across their sublevels.
Remember that bromine (Br) is a halogen, meaning it has 7 valence electrons (in the 4p sublevel).
