An atom of helium can store energy by bumping an electron from its lowest orbital energy state to a higher orbital energy level. In particular, moving an electron from the lowest state to the next-lowest state would store an energy of $24.6 \mathrm{eV}$. Why can we ignore this energy storage mode when calculating the heat capacity of helium gas?
A) This mode is "frozen" out at normal temperatures.
B) Collisions between atoms can't influence the energy levels of electrons inside the atoms.
C) This storage mode is completely independent of the kinetic and/or rotational energy modes.
D) Only modes involving helium molecules count.
E) We have ignored this mode only for simplicity's sake.
F) Some other reason (specify).

Question

Quizplus · Accepted Answer

This mode is considered "frozen" out at normal temperatures because the energy required to excite an electron to a higher orbital level (24.6 eV) is much higher than the thermal energy available at these temperatures. Therefore, electronic excitation does not significantly contribute to the heat capacity of helium gas under normal conditions.

An Atom of Helium Can Store Energy by Bumping an Electron