Why do the negative ions have larger radii than the positive ions?

Protons and electrons have opposite charges, and they pull on each other. Negatively charged ions have more negative charges inside of them, which causes the electrons to move away from the nucleus in a manner similar to how magnets repel, while positively charged ions have stronger positive charges inside of them and pull their electrons closer to them in a manner similar to how magnets attract. As a result, when an atom turns into a positive ion, its electrons move closer together, decreasing its radius, and vice versa.

The positive nucleus stays the same, with the same attractive force, but this force is now pulling on more electrons and so has less effect; this means with more electrons but the same number of positive protons, the size of the ionic radius will increase. When an atom attracts additional electrons, it becomes a negative ion, which is larger than the original atom.

When an atom's electrons are drawn to another atom, it becomes a positive ion, which is smaller than the parent atom. The positive nucleus is still present and has the same attractive force, but it is now pulling on fewer electrons, which means that the size of the ionic radius will decrease when there are fewer electrons but the same number of positive protons.

The negative ion will be larger than the positive ion because the formation of a negative ion increases the ionic radius while the formation of a positive ion decreases it.

Since negative ions have gained one or more electrons, they have larger radii than positive ions because the electron cloud expands due to the electron-electron repulsion, which in turn causes a larger atomic or ionic radius.