An atom of hydrogen undergoes a collision with another atom in a hot gas in which the energy of collision is about 11 eV.What is the likely outcome of this collision in terms of the atom? (See Figure 3-51,Comins,Discovering the Essential Universe,6th ed.)
A) The electron in the atom will be excited to the second excited level, n = 3, and de-excitation will generate either an Lα UV Lyman photon or an Hα visible and an Lα UV photon.
B) The electron in the atom will be excited to the first excited level, n = 2. Its return to the ground state will produce an Lα UV Lyman photon.
C) The electron in the atom will be excited to the first excited level, and de-excitation to the ground state will produce a visible photon of Balmer Hα light.
D) The electron of the hydrogen atom will be excited beyond the ionization level (n = ∞); the atom will be ionized, and the electron will leave the atom completely.

Question

Quizplus · Accepted Answer

When an atom undergoes a collision with another atom and gains energy, its electron can be promoted to a higher energy level. In this case, the energy of collision is about 11 eV, which is enough to excite the electron of the hydrogen atom to the first excited level (n=2). When this electron returns to the ground state, it emits an Lα UV Lyman photon. Therefore, the most likely outcome of this collision is that the electron in the atom will be excited to the first excited state, n=2. Its return to the ground state will produce an Lα UV Lyman photon. Choice A is incorrect because an energy of 11 eV is not sufficient to excite the electron to the second excited level. Choice C is incorrect because the energy of collision is in the Lyman series, not the Balmer series. Choice D is incorrect because the energy of collision is not high enough to ionize the hydrogen atom.

An Atom of Hydrogen Undergoes a Collision with Another Atom