Name:
Block:
Date:
Partner(s):
2012

2013
IC
Ch. 4 and 11:
Activity

Electron Cloud Distribution
Question:
What is the probable distribution of locations around a central point? How does this relate to
the location of electron (electron distribution) around the nucleus?
Materials:
fe
lt tip pen; paper target; graph paper (provided)
The exact position of an electron in an atom at any given moment cannot be determined. However, the
region of space in which the electron can
probably be found
is predictable. This region is called the
“
electron cloud” and is often represented as a fuzzy shape with the nucleus at its center. The shape of the
cloud is determined by mathematical calculations using Schrödinger’s quantum mechanical model of the
atom. The electron cloud is defined as the reg
ion in space where an electron is found 90% of the time. The
90% probability means that about 10% of the time, the electron may be found outside of the electron cloud.
Instructions:
1.
Place your paper target
on a notebook
on the floor. Drop the marker (p
oint down) from a height of about
1 meter onto the target so that it makes a mark. Try to hit the center! Repeat 100 times. (Yes, 100
times…it won’t take
that
long!).
2.
Count the number of marks in each numbered region of the target, and record the numbe
rs in the table
below.
Region
Number of Marks
1
2
3
4
5
>5
Analysis/Questions:
1.
Plot your results on the graph, with Number of Marks on the y

axis and Region Number on the x

axis.
2.
Determine from your graph which target region had the
highest probability of a hit.
3.
How does the shape of your graph compare to the graph of Electron Probability versus Distance from
Nucleus for the hydrogen electron
provided by the teacher
?
4.
How is the spherical electron cloud picture similar to y
our target? How is it different?
5.
Can the spherical electron cloud be thought of in another way, using an example or model from
everyday life?
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