Final answer:
The atom with the given electron configuration has four valence electrons, which are located in the outermost 5s and 5p sublevels. Therefore correct option is B
Step-by-step explanation:
The atom with the electron configuration 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p² has four valence electrons. Valence electrons are the electrons in the outermost energy level of an atom that can participate in chemical bonding.
In this case, the outermost energy level is the fifth shell (n=5), which includes 5s² and 5p².
The 's' and 'p' sublevels in this shell contain a total of four electrons, so the answer is four valence electrons (option b).