### Video Transcript

Who established the quantum
mechanical model of the atom?

In this question, we need to
determine who established the quantum mechanical model of the atom. Let us first describe the Bohr
model of the atom. And then we can then explain the
quantum mechanical model of the atom and who theorized it.

Niels Bohr was a famous Danish
physicist who explained the emission spectrum of hydrogen. He did this by theorizing that
electrons orbit nuclei much like planets orbit the Sun. The figure describes the Bohr model
using a representative beryllium atom. We see that the electrons are
supposed to orbit the positively charged nucleus at a set radii. The energy state of each electron
was supposed to be determined by the radius of its orbit. Electrons were supposed to have a
relatively low energy state if they had a small radius. They were supposed to have a
relatively high energy state if they had a large radius.

This scientific model
satisfactorily explains the emission spectrum of hydrogen. However, it does not explain the
emission spectra of other elements with a higher atomic number. The quantum mechanical model of the
atom proposed an altogether different model for the structure of the atom. This model stated that electrons do
not orbit atomic nuclei at set radii with a well-defined position. This model showed that it is more
accurate to describe electrons as three-dimensional clouds of negatively charged
density.

The figure shows the electrons of a
beryllium atom according to the quantum mechanical model. We see that two electrons form one
spherical cloud of electron density is called the 1s orbital. We can also see that the other two
electrons form a different spherical cloud system of electron density called the 2s
orbital. We should note that density is not
uniform throughout these clouds of electron density.

It should be clear that the Bohr
and quantum mechanical models for atomic structure are fundamentally different,
since they describe the location of electrons differently. Erwin Schrödinger, an Irish
physicist, developed the quantum mechanical model of the atom, which satisfactorily
explains more scientific phenomena than the Bohr model and is the basis for modern
quantum chemistry.

In conclusion, after comparing the
two models for the electron location within the structure of the atom, we should now
understand that Schrödinger established the quantum mechanical model of the
atom.