* Electron Configuration: Bromine (Br) has an atomic number of 35, meaning it has 35 protons and 35 electrons in its neutral state. Its electron configuration is [Ar] 3d10 4s2 4p5. This means it has 7 valence electrons in its outermost shell.
* Gaining an Electron: When bromine gains an electron, it fills its outermost shell, making its configuration [Ar] 3d10 4s2 4p6. This complete outer shell is a very stable configuration.
* Ionic Charge: Because it has gained a negatively charged electron, the bromine atom now has one more electron than protons. This results in a net negative charge of -1, making it a bromide ion (Br-).
* Increased Size: The bromide ion is larger than the neutral bromine atom. This is because the added electron increases the repulsion between electrons, pushing the electron cloud outwards.
In summary: The addition of an electron to bromine results in a stable, negatively charged bromide ion (Br-) with a complete outer shell and an increased atomic radius.
