How to read an electron table.
When you are making your model of the atom you will need to know
how to place the
electrons around the nucleus. Before you can make the model you
will need to know how to
read an element's electron configuration. Follow these
directions.
What is an electron configuration table?
An electron configuration table is a code that describes how
many electrons are in each energy level of an atom and how the
electrons
are arranged within each energy level. It packs a lot of information
into a little space and so it takes a little practice to read.
This for
example, is the electron configuration table for gold:
What do all those numbers and letters mean?
Each row of an electron configuration table is like a sentence.
Each 'sentence' is made up of smaller 'words'. Each 'word' follows
this format:
The first number is the energy level. We can tell right away that
an atom of gold contains 6 energy levels. The lowercase letter is
the sub-shell. The sub-shells are named s, p, d and f. The number
of available sub-shells increases as the energy level increases. For
example, the first energy level only contains an s sub-shell while
the second energy level contains both an s sub-shell and a
p sub-shell.
The number in superscript ( for example 2p6 ) is the
number of electrons in a sub-shell.
Each sub-shell can hold only a certain number of electrons. The
s sub-shell
can hold no more than 2 electrons, the p sub-shell can hold 6, the
d sub-shell can hold 10
and the f sub-shell can
hold as many
as 14.
How can I use the electron configuration table to tell me...
How many energy levels does an atom have? Since the electron
configuration
table lists each energy level by row, you can tell how many energy
levels there are by seeing how many rows there are. As was mentioned
earlier, an atom of gold contains six energy levels, as shown below:
How many electrons are in each energy level?
The total number of electrons in an energy level is the sum of the
electrons in each sub-shell of that energy level. Just add the numbers
in superscript ( i.e. 2p6 )
together to find the number of electrons in an energy
level. The number of electrons in each energy level in an atom of
gold is shown below:
How many electrons are in an atom's outer energy level?
This is just a combination of the previous two examples. Use the
electron
configuration to find that atom's highest energy level and then add
up the numbers in superscript to find the number of electrons that
are in it. There is one electron in the outer energy level of an atom
of gold, as shown below:
File translated from
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version 3.70.
On 13 Nov 2007, 20:52.
