Atomic Theory Class #3
OB: patterns of the electron orbitals
as related to the Periodic Table of
the Elements, ground and excited
states of the electrons, + spectra
Using your white periodic tables, write out the electron configurations of the following:
Group
1
Group
2
Group
15
Group
16
Group
17
Group
18
lithium
beryllium
nitrogen
oxygen
fluorine
neon
sodium
magnesium
phosphorous
sulfur
chlorine
argon
rubidium
strontium
antimony
tellurium
iodine
Xenon
Using your white periodic tables, write out the electron configurations of the following:
Group
1
Group
2
Group
15
Group
16
Group
17
Group
18
lithium
beryllium
nitrogen
oxygen
fluorine
neon
2-1
2-2
2-5
2-6
2-7
2-8
Using your white periodic tables, write out the electron configurations of the following:
Group
1
Group
2
Group
15
Group
16
Group
17
Group
18
lithium
beryllium
nitrogen
oxygen
fluorine
neon
2-1
2-2
2-5
2-6
2-7
2-8
sodium
magnesium
phosphorous
sulfur
chlorine
argon
2-8-1
2-8-2
2-8-5
2-8-6
2-8-7
2-8-8
Using your white periodic tables, write out the electron configurations of the following:
Group
1
Group
2
Group
15
Group
16
Group
17
Group
18
lithium
beryllium
nitrogen
oxygen
fluorine
neon
2-1
2-2
2-5
2-6
2-7
2-8
sodium
magnesium
phosphorous
sulfur
chlorine
argon
2-8-1
2-8-2
2-8-5
2-8-6
2-8-7
2-8-8
rubidium
strontium
antimony
tellurium
iodine
xenon
2-8-18-8-1
2-8-18-8-2
2-8-18-18-5
2-8-18-18-6
2-8-18-18-7
2-8-18-18-8
The 1st orbital holds up to 2 electrons
The 2nd orbital holds up to 8 electrons
While the 3rd orbital holds up to 8 or 18 electrons,
and the 4th orbital holds up to 18 or 32 electrons
All electron orbitals on the periodic table are
in the LOWEST ENERGY state, also called the
GROUND STATE.
Atoms + their electrons can get energized, and they can get excited.
ground state
A possible
excited state
lithium
lithium
2-1
sodium
sodium
2-8-1
potassium
potassium
2-8-8-1
rubidium
2-8-18-8-1
rubidium
ground state
A possible
excited state
lithium
lithium
2-1
sodium
1-2
sodium
2-8-1
potassium
2-7-2
potassium
2-8-8-1
2-8-7-2
rubidium
rubidium
2-8-18-8-1
2-8-18-7-2
Ground + Excited State
electron configurations
have the
SAME NUMBER OF ELECTRONS,
they are just in
DIFFERENT PLACES
For example…
Sodium in ground state is 2-8-1 electron configuration
Possible excited states include:
1-8-2
2-7-2
1-7-3
2-6-3
Which ones are possible? In our class that question is way to hard to answer.
Let’s stick to simple excited states. No excited state that you can imagine would
be wrong, because “what is possible” is outside the scope of this course, and
I don’t really know all the answers anyway.
You won’t be “wrong” by choosing 1-5-7,
but let’s be calm: that’s way funkier than
the simple 2-7-2 configuration.
You know what this is?
How do these electrons get excited?
Energy can be added into atoms, by
heating, electricity, radiation, etc.
A unique amount of energy is required to move an electron in any
atom or compound.
Each atom, or compound, has a unique set up of protons and
electrons in orbitals. Different atoms with the same number of
orbitals (say sodium and magnesium, 3 orbitals each) have
different numbers of protons “pulling” on the electrons. To make
one Na e― jump from the 2nd  3rd orbital is a different, unique
amount of energy than the Mg atom, because of different number
of protons in their nucleus.
Atom
Number of
protons in
Electrons living
nucleus with +
in these orbitals
charge pulling on
the electrons
Sodium Na
11 protons
2-8-1
Magnesium Mg
12 protons
2-8-2
To excite an electron in the second orbital into
the third will take different amounts of energy
because of the different arrangements of
protons and electron in different atoms.
A unique amount of energy into the atom, to excite the electrons is required
for each electron of each atom or compound.
When this unstable situation resolves itself (quickly usually), the unique
amount of energy is released.
No matter how the energy was added in, most of the energy coming out is
emitted as visible light.
Each unique amount of energy given off is visible as different colors, which we
can see with our eyes.
And if we wear
refractive lenses,
we can se it even
better!
Energy In, HEAT
for example 2
Electrons in an atom
or compound,
1
ground state
Electrons in an atom
or compound,
3
excited state
4 4
Energy Out
1.
2.
3.
4.
Matter is in the ground state normally
Energy is inserted, here by heating
The atoms or atoms in compounds become excited by the gained energy
The electrons are unstable in the excited state, so they return to the ground state,
giving off that energy they previously absorbed, as visible – colorful light (spectra)
Each atom has a mixture of light given off that we see as one color with our eyes.
The mixture can be broken apart by refractive lenses.
Neon gas, when excited gives off orange light to the eyes.
If we look at this with a refractive lens, this is what
we will see (the actual colors that mix, to form one
color for our eyes.
We will see spectra in the ELECTRONS lab, next week.
Each spectra is unique, like a fingerprint for each atom, and for each compound.
Spectra can be used to determine what unknowns you may have in your hand,
or may exist on a distant planet (using a telescope).
Be psyched.
Understanding this all goes
to Niels Bohr, who was
quite a guy.
Read the Atomic Theory Diary
Atomic HW # 1
due Thursday