Question

which of the following electron configurations is the correct one for the element bromine? a) 1s22s22p63s23p6 b) 1s22s22p63s23p64s23d104p6 c) 1s22s22p63s23p64s23d104p5 d) 1s22s22p63s23p5

Explanation:

Step1: Recall bromine's atomic number

Bromine has atomic number 35.

Step2: Write electron - filling order

Electrons fill orbitals in order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p.

Step3: Calculate electrons in each orbital

1s² has 2 electrons, 2s² has 2 electrons, 2p⁶ has 6 electrons, 3s² has 2 electrons, 3p⁶ has 6 electrons, 4s² has 2 electrons, 3d¹⁰ has 10 electrons, 4p⁵ has 5 electrons.
2 + 2+6 + 2+6 + 2+10 + 5=35.
The electron - configuration of bromine is 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵.

Answer:

d) 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵