Bromine is a chemical element with symbol Br and atomic number 35. It is a halogen. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jérôme Balard.
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Answer: Br
Explanation:
[tex]Br:35:[Ar]3d^{10}4s^24p^5[/tex]
[tex]Br^-:36:[Ar]3d^{10}4s^24p^6:[Kr][/tex]
[tex]Na:11:[Ne]3s^1[/tex]
[tex]Na^-:12:[Ne]3s^2[/tex]
[tex]Al:13:[Ne]3s^23p^1[/tex]
[tex]Al^-:14:[Ne]3s^23p^2[/tex]
[tex]S:16:[Ne]3s^23p^4[/tex]
[tex]S^-:17:[Ne]3s^23p^5[/tex]
As Bromine is short of only 1 electron to attain noble gas configuration, it will release energy as more stable species have less energy. Thus bromine would release most energy while adding an an electron to a neutral atom in the gas phase.
All other species Na, Al and S would not attain stable configuration on addition of electron and hence no energy would be released.
