• Do the electrons follow defined paths around the nucleus?
If the electron revolves around the nucleus in defined paths or orbits,
the exact position of the electron at various times will be known. For that
we have to answer two questions:
• What is the velocity of the electron?
• Is it possible to find the exact position of the electron?
Electrons are invisible to naked eye. Then, how do you find the position
and velocity of an electron?
To find articles during dark nights we take the help of torchlight.
Similarly, we can take the help of suitable light to find the position and
velocity of electron. As the electrons are very small, light of very short
wavelength is required for this task.
This short wavelength light interacts with the electron and disturbs the
motion of the electron. Hence, simultaneously the position and velocity
of electron cannot be measured accurately.
From the above discussion, it is clear that electrons do not follow
definite paths in an atom.
Do atoms have a definite boundary, as suggested by Bohr’s model?
If the electrons are not distributed in orbits around the nucleus this
means that an atom does not have a definite boundary.
As a result, it is not possible to pinpoint an electron in an atom.
Under these circumstances in order to understand the properties of
electrons in an atom, a quantum mechanical model of atom was developed
by Erwin Schrodinger.
According to this model of an atom, instead of orbits of Bohr’s model,
the electrons are thought to exist in a particular region of space around the
nucleus at a given instant of time
• What do we call the region of space where the electron might be, at a
given time?
The region of space around the nucleus where the probability of
finding the electron is maximum is called an orbital.