Problem 24 - Chemistry: An Atoms-Focused Approach

Question

Which of the following cannot be measured: ionization energy, electron affinity, ionic radius, atomic radius, or electronegativity?

Step-by-Step Solution

Answer

Answer: Electronegativity.

Step 1: Define each property

Ionization energy is the energy required to remove an electron from an atom or ion. Electron affinity is the energy change associated with the addition of an electron to a gaseous atom. Ionic radius is the measure of an ion's size. Atomic radius is the distance from the nucleus of an atom to its outermost shell of electrons. Electronegativity is the tendency of an atom to attract a shared pair of electrons.

Step 2: Determine whether each property can be measured

Ionization energy can be measured through experimental methods such as photoelectron spectroscopy. Electron affinity can also be measured experimentally, although the process may be less direct. Ionic radius and atomic radius can be determined through various experimental techniques like X-ray crystallography and electron diffraction. The only property listed that cannot be directly measured is electronegativity. Electronegativity is an empirical, dimensionless quantity that is derived rather than measured.

Step 3: Provide the answer

Of the given properties, electronegativity cannot be directly measured.