Question

question 5 (1 point)
which is the correct electron configuration for the element bromine (br)?
o a 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵
o b 1s²2s²2p⁶3s²3p⁶4s²4d¹⁰
o c 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰3p⁵
o d 1s²2s²2p⁶3s²3p⁶4s²3d⁴

Explanation:

Step1: Recall atomic number of bromine

Bromine has an atomic number of 35, so it has 35 electrons.

Step2: Apply electron - filling rules

Electrons fill orbitals in the order 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p. The 1s orbital can hold 2 electrons, 2s can hold 2, 2p can hold 6, 3s can hold 2, 3p can hold 6, 4s can hold 2, 3d can hold 10, and 4p can hold 6.
Filling the orbitals: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵ gives a total of 2 + 2+6 + 2+6 + 2+10 + 5=35 electrons.

Answer:

A. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵