Which is the electron configuration for bromine?
O 1s22s22p 3s23p64s²3d¹04p5
O 1s²2s22p 3s23p64s23d¹04p6
O 1s²2s22p 3s23p44s²3d¹04p5
O 1s22s22p63s23p64s23d94p5