Question

Which of the following ions has a noble gas electron configuration?

a) Na+
b) O2-
c) Cl-
d) Mg2+

Answer 1

Each ion, Na+, O2-, Cl-, and Mg2+, achieves a noble gas electron configuration by reaching a full outer electron shell similar to neon or argon after losing or gaining electrons.

Step-by-step explanation:

The question asks which of these ions has a noble gas electron configuration. A noble gas electron configuration means having a complete outer shell of electrons, identical to the electron configuration of a noble gas. The ions that are being considered are:

• Na+
• O2-
• Cl-
• Mg2+

Each of these ions attains a noble gas electron configuration by gaining or losing electrons:

• Na+ loses one electron to have the same electron configuration as neon (Ne).
• O2- gains two electrons to have the same electron configuration as neon (Ne).
• Cl- gains one electron to have the same electron configuration as argon (Ar).
• Mg2+ loses two electrons to have the same electron configuration as neon (Ne).

Each of these ions, Na+, O2-, Cl-, and Mg2+, attains a noble gas electron configuration when they gain or lose the correct number of electrons.