The atomic orbitals of two bromine atoms combine to form the diatomic br2 molecule. use the periodic table to determine the atomic orbitals that overlap to form the br2 molecule and the symbol of the noble gas that has the same electron configuration as the electron configuration of each bonded bromine atom.
for example, the 2p atomic orbitals of fluorine atoms overlap to form the f2 molecule. the noble gas that has the same electron configuration as that of each bonded fluorine atom is ne. to enter the atomic orbitals that overlap and the corresponding noble gas, you would enter 2p, ne.

[Ar] 3d10 4s2 4p5

Explanation:

Remember that noble gases are elements that have all of their orbitals full, this means that they are complete and are almost not reactant because chemically they do not need to react with others to complete their orbitals, the electronic configuration of the element Bromo, the atomic orbitals would be [Ar] 3d10 4s2 4p5 since is the noble gas prior to the atomic number plus the uncompleted orbitals, and the last one one be 4p5, Ar

the atomic number will stay the same no matter how many electrons it has, so it doesn’t decrease nor increase. it’ll only change with a different number of protons