Ions formed from main‑group elements have the same electronic structure as the noble gases , which are the elements in Group 0 (also called Group 18) of the periodic table.

In other words, when atoms gain or lose electrons to become ions, they usually do so in order to achieve the full outer shell electron configuration characteristic of Group 0/18 noble gas atoms (like neon or argon). So the answer to:

“ions always have the same electronic structure as elements in which group of the periodic table?”

is: Group 0 (Group 18), the noble gases.

Quick Scoop: Why Group 0?

  • Atoms are most stable when they have a full outer electron shell, and noble gases naturally have this full outer shell.
  • Other elements form ions (by losing or gaining electrons) specifically to match this stable noble-gas configuration.
  • For example, sodium (Na) loses one electron to form Na⁺, which has the same electronic structure as neon, a Group 0 element.

So, in exam-style format:
Answer (as a group number): 0 (or 18 , depending on your periodic table convention, but typically written as Group 0 for this type of question).

TL;DR: Ions are formed to imitate the full outer shell of Group 0/18 noble gases , giving them the same electronic structure as those elements.

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