Which of the following would have to gain two electrons in order to achieve a noble gas electron configuration _ ?
O Sr Na Se Br
A) Br
B) Sr, O, Se
C) Sr
D) O, Se
E) Na

Question

Quizplus · Accepted Answer

The noble gas electron configuration for oxygen would be 2s^2 2p^6. Therefore, oxygen would need to gain 2 electrons. The noble gas electron configuration for selenium would be 3s^2 3p^6. Therefore, selenium would also need to gain 2 electrons to reach noble gas configuration. Na already has a noble gas configuration (neon). Bromine would need to gain one electron to achieve a noble gas configuration of krypton. Sr already has a noble gas configuration (krypton). Therefore, the correct answer is choice D, as both Oxygen and Selenium must gain two electrons.

Which of the Following Would Have to Gain Two Electrons