Question

O\(_2^{−}\), F\(^−\), Mg\(^{2+}\), Al\(^{3+}\), O\(_2\), F\(_2\). How many of the species given above are isoelectronic?

• A. 4
• B. 2
• C. 3
• D. 5

Hint:

To check if species are isoelectronic, simply compare the total number of electrons. Species with the same number of electrons are isoelectronic.

Answer 1

The Correct Option is A

To determine how many species are isoelectronic, we need to count the number of electrons in each species. - O\(_2^{−}\) has 10 electrons (O has 8, plus 2 electrons from the charge).
- F\(^−\) has 10 electrons (F has 9, plus 1 electron from the charge).
- Mg\(^{2+}\) has 10 electrons (Mg has 12, minus 2 electrons from the charge).
- Al\(^{3+}\) has 10 electrons (Al has 13, minus 3 electrons from the charge).
- O\(_2\) has 16 electrons (O has 8, multiplied by 2 atoms).
- F\(_2\) has 18 electrons (F has 9, multiplied by 2 atoms). Thus, O\(_2^{−}\), F\(^−\), Mg\(^{2+}\), and Al\(^{3+}\) are isoelectronic, so there are 4 species that are isoelectronic.