What is atomic radii and how is this impacted in ions?

Since the protons in an atom constitute its nucleus, the nucleus attracts electrons more strongly than the electrons in an atom, which is why the atomic radii decrease with increasing atomic number. For example, lithium number three is larger than nitrogen number ten because the electrons in lithium number three are in the same electron shell but are less attracted to the nucleus.

The + 1 ion is significantly smaller than the atomic radii of the neutral atom, though, because even if the third electron in the lithium atom is lost, leaving only two electrons in a smaller electron shell, three positive charges are still pulling on the remaining two electrons.

Even though there are still nine positive protons pulling on the electrons in the case of Flourine atomic number nine gaining an electron, the pull is now less strong because there are now ten electrons being drawn in by the same positive charge. As a result, the -1 ion is larger than the neutral atom.

Atomic radii refer to the size of an atom, typically measured as the distance from the nucleus to the outermost electron shell. In ions, the atomic radii can be impacted depending on whether the ion has gained or lost electrons. When an atom gains electrons to form a negative ion (anion), its atomic radius increases because the additional electrons create more electron-electron repulsion, pushing the electron shells further apart. Conversely, when an atom loses electrons to form a positive ion (cation), its atomic radius decreases because there are fewer electrons to repel each other, resulting in the remaining electrons being drawn closer to the nucleus.