An element that has the same ground state valence-shell electron configuration as thallium is
A) gallium.
B) carbon.
C) krypton.
D) cesium.
E) magnesium.

Question

Quizplus · Accepted Answer

Thallium has a valence-shell electron configuration of 6s2 6p1. Gallium also has a valence-shell electron configuration of 4s2 4p1, which is the same as 6s2 6p1 when considering the Aufbau principle. The other choices have different valence-shell electron configurations.

An Element That Has the Same Ground State Valence-Shell Electron