Question

Write the electron configuration for Br- and state the number of valence electrons. Select one:

a. 1s22s22p63s23p64s24p5 with 5 valence electrons
b. 1s22s22p63s23p64s23d104p65s25p5 with 5 valence electrons
c. 1s22s22p63s23p64s23d104p6 with 8 valence electrons
d. 1s22s22p63s23p64s23d104p65s24d105p5 with 7 valence electrons

Answer 1

`1s^(2) 2s^(2) 2p^(6) 3s^(2) 3p^62} 4s^(2) 3d^(10) 4p^(5)` with 7 valence electrons.

Step-by-step explanation:

Bromine has 7 unpaired (valence) electrons in its outer shell, and a total of 35 elecrons. Its 4s orbital is completely filled with 2 electrons.

The closest answer from the options would be option D.

I hope this helps.