Why, in terms of atomic structure, is the radius of an Na atom larger than the radius of an Na+ ion?

Na atom is 1s2 2s2 2p6 3s1

Na^+ is 2s2 2s2 2p6. The outside electrons is missing; the radius is smaller.

thanks

In terms of atomic structure, the radius of an atom is determined by the arrangement of electrons and the attractive force between the protons in the nucleus and the electrons.

When an atom loses one or more electrons and becomes an ion, the number of electrons changes, which affects the overall electronic configuration of the atom. In the case of Na, the neutral sodium atom (Na) has 11 electrons, arranged in three energy levels or shells around the nucleus.

However, when sodium loses one electron to form Na+ ion, it now has 10 electrons. Due to the loss of one electron, the electron-electron repulsion is reduced, and the remaining electrons are pulled closer to the nucleus by the stronger force of attraction between the positively charged protons and the negatively charged electrons.

This means that in the Na+ ion, the outermost electron is closer to the nucleus compared to the neutral Na atom. As a result, the effective nuclear charge experienced by the remaining electrons in the Na+ ion increases, which leads to a smaller atomic radius compared to the neutral Na atom.

To summarize, the radius of an Na atom is larger than the radius of an Na+ ion due to the loss of an electron in the ion, resulting in a stronger attraction between the remaining electrons and the nucleus.