Question

Which would have the largest atomic size: O²⁻, F⁻, F, Na⁺, Mg²⁺? And why?

Answer 1

The order of atomic sizes would be O²⁻ > F⁻ > F > Na⁺ > Mg²⁺.

Step-by-step explanation:

The atomic size or atomic radius refers to the size of an atom. It is measured as the distance between the nucleus of an atom and the outermost shell of electrons. In general, the atomic size increases down a group and decreases across a period in the periodic table.

1. O²⁻: This ion has gained two electrons, resulting in an increased electron-electron repulsion. Therefore, it would have a larger atomic size compared to its neutral atom, oxygen (O).
2. F⁻: This ion has gained one electron, which increases the electron-electron repulsion. Hence, it would also have a larger atomic size compared to its neutral atom, fluorine (F).
3. F: The neutral fluorine atom has a smaller atomic size compared to the F⁻ ion since it has one less electron.
4. Na⁺: This ion has lost one electron, reducing the electron-electron repulsion and making it smaller in size compared to its neutral atom, sodium (Na).
5. Mg²⁺: This ion has lost two electrons, resulting in less electron-electron repulsion and a smaller atomic size compared to its neutral atom, magnesium (Mg).

Therefore, in terms of atomic size, the order would be: O²⁻ > F⁻ > F > Na⁺ > Mg²⁺.