Answer:
Bromine(BR) 1s(1) 2s(2) p(6), 3s(2) p(6),3d(10)4s(2), p(5)
Explanation:
Group 7A elements have a -1 electron configuration.
Beginning at the top left and going across the rows of the periodic table provides a method for remembering the order
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p.
