Question

Question: The “radius of an atom” is a debatable quantity. Why?

Short answer

Answer

Half the distance between the nuclei of identical neighboring atoms in the solid form of an element.

Step-by-step solution

Radius of the atom

The radius of an atom is about 0.1 nm ($1\times {10}^{-10}m$)

The wave function for the electrons in atoms does not have an abrupt change to zero at some specific radius and beyond Instead, the wave function.

Explanation.

And therefore the probability density for finding an electron at a given distance from the nucleus falls off exponentially with a tail that extends to infinite distance once the distance is large enough. It is therefore somewhat ambiguous to decide at what distance the probability of finding an electron has become small enough to regard that location as outside the radius of the atom.