Video Transcript
In the Bohr model of the hydrogen
atom, which of the following is correct? (A) The electron occupies the
energy level furthest from the nucleus to generate its ground state. (B) The electron occupies the
energy level nearest to the nucleus to generate its ground state. (C) The electron occupies the
energy level nearest to the nucleus to generate its excited state. Or (D) the electron occupies the
space between energy levels to generate its ground state.
This question refers to the Bohr
model of the atom, which suggested that electrons move around the nucleus in flat
circular orbits. The Bohr model also suggested that
the energy of the electrons in those orbits is directly proportional to the radii of
their orbits. Because the question is referring
to a hydrogen atom, the atom would contain only one electron and one proton. The answer choices given all refer
to either the behavior of an electron in what is called its ground state or its
excited state.
An electron in its ground state is
occupying the lowest possible energy state. In other words, the electron will
occupy the closest possible energy level to the nucleus. As radius and energy are
proportional, the energy level with the smallest radius will have the lowest
energy. When an electron is in its excited
state, it is promoted out of its ground state by absorbing energy and thus moves to
a higher energy level. Now occupying an energy level that
has a larger radius, the electron is in a higher energy state.
It is worth noting that this
electron excitement is temporary, and after releasing a certain amount of energy,
often in the form of light, the electron returns to its ground state. Let’s have a look at our answer
choices.
Answer choice (A) suggests that for
an electron to be in its ground state, it will occupy an energy level as far from
the nucleus as possible. We have seen that this is opposite
to what is true for an electron in the ground state. We can eliminate answer choice
(A).
Answer choice (B) describes exactly
what occurs for an electron in its ground state. Answer choice (B) is the correct
answer. Let’s have a look at answer choices
(C) and (D) just to be sure.
Answer choice (C) suggests that for
an excited electron, it must be in an energy level as close to the nucleus as
possible. This is true for an electron in the
ground state, but not the excited state. We can eliminate answer choice
(C).
Answer choice (D) suggests that
ground state electrons can occupy spaces between energy levels. The Bohr model of the atom
suggested that it was not possible for electrons to be in between orbits, but that
they must occupy the fixed energy levels. We can eliminate answer choice
(D).
Therefore, the statement that
correctly describes the Bohr model of the hydrogen atom is answer choice (B), the
electron occupies the energy level nearest to the nucleus to generate its ground
state.
