3.3 – THE QUANTUM MECHANICAL MODEL OF THE ATOM
Quantum Mechanics
Remember, that the way we have looked at electrons thus far is
that they simply move around a nucleus within an atom in a
specific path. We know from last year, that that is not true.
Erwin Schrodinger theorized that electrons have
and exhibit wave behavior. Schrodinger believed that the
electron is a
around the
nucleus. This fit with the idea of his predecessors, who said the
electrons possessed energy of fixed quanta.
The following diagram shows what is known as
a standing wave, because they look
stationary. You will see this effect when you
pluck a string instrument. Label the diagram
to show the different parts of a wave on the
left.
THE IDEA OF ORBITALS
Consider the following: How can we determine the speed and location of people? Of cars?
The problem is that is impossible to know the specific location and speed of an electron in an
atom at a given time. This is called the
. Because of
this uncertainty, the idea of the orbital came about. An orbital is an
. It helps to think of the orbital
as kind of like a cloud(s) around the nucleus.
combine math and chemistry to help us figure out the probability of
locating an electron in a particular region. Wave functions have helped us to determine
which is the probability of finding an electron at a given
location. The probability density for the single electron in the hydrogen atom is
in shape and is called the
orbital.
What do you think the following diagram to the right is showing?
If electrons have enough packets of energy (What is the word
to use here?) they can jump from one orbital to another.
So moving away from our understanding of the early models of
the atom, we have the QUANTUM MECHANICAL MODEL.
Summarize it below:
HOMEWORK: Read Page 148-151 and do questions #1-4, 6-8, 10 BONUS