Which atom or ion would you expect to have the smallest radius?
Ne
F-
Na+
Ne-
To determine which atom or ion would have the smallest radius, we need to consider the atomic and ionic structures.
The atomic radius generally decreases from left to right across a period and increases down a group in the periodic table.
In this case, we are comparing Neon (Ne), Fluoride ion (F-), Sodium ion (Na+), and Neon ion (Ne-).
Neon (Ne) is a noble gas located in Group 18 (or 8A) of the periodic table. It has a full electron shell, which means it has the highest effective nuclear charge and the smallest atomic radius among the options given.
Fluoride ion (F-) is formed by adding an extra electron to the neutral fluorine (F) atom. Adding an electron to an atom increases the electron-electron repulsion, causing the electron cloud to expand. Therefore, F- will have a larger radius than the neutral fluorine atom.
Sodium ion (Na+) is formed by removing an electron from the neutral sodium (Na) atom. Removing an electron decreases the electron-electron repulsion, causing the electron cloud to contract. Therefore, Na+ will have a smaller radius than the neutral sodium atom.
Neon ion (Ne-) is formed by gaining an extra electron by the neutral neon (Ne) atom. Similar to the fluoride ion, adding an electron to an atom will increase the electron-electron repulsion, causing the electron cloud to expand. Therefore, Ne- will have a larger radius than the neutral neon atom.
So, based on this information, we can conclude that the atom or ion with the smallest radius would be Neon (Ne).