The Begenius School of
Atom Model Drawing
Everything you wanted to know to
pass your next quiz on atoms
People, Theories, and Models
Democritus – ancient Greek that
named the atom after “atomos”
which means indivisible.
 Aristotle argued against this idea
suggesting that matter could be
divided infinitely.
 John Dalton – first chemist that
made the first table of elements
and was the first to suggest that
atoms of gold were unique and
different from atoms of iron. He
had a theory called the billiard ball
model of atoms…suggesting that
atoms were like balls that collide
with each other and have unique
masses and properties.
 Dalton proved in 1802 that atoms
were real and he pictured them as
small billiard balls. He used an
example that if you had some gold
each atom would be solid gold.
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More about People, Theories, and
Models
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In1897 J.J. Thomson
published a theory called
the Plum Pudding
Model of an atom.
His model put the first
electrical quantities into
the model called
electrons.
The electrons were seen
as negative charges and
the pudding part of the
model was seen as a
positively charged
material making up the
rest of the atom.
Plum Pudding Model
Even more about people, theories
and models
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In 1911 Ernest
Rutherford disproved the
plum pudding model by
proving the existence of a
nucleus which held most
of the mass and an
empty space between the
nucleus and the orbits of
electrons.
Eventually this grew into
our model that has
protons and neutrons in
the nucleus and electrons
in orbits spinning around
the nucleus.
Final notes about people, theories
and models
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Niels Bohr applied
quantum physics to the
model of the atom in
1913 and added a
specific orbital/energy
level concept to the
atom.
Each atom is now seen as
having a specific pattern
of space where electrons
can be found called s, p,
d, and f orbitals.
Final notes about people, theories
and models
The electron cloud model puts all
of the parts of the atom into high
speed motion, and suggest that
we never really know exactly
where electrons will be but that
there are regions where we may
find them.
 Erwin Schrodinger is credited with
the cloud model.
 The cloud model represents a sort
of history of where the electron
has probably been and where it is
likely to be going. The red dot in
the middle represents the nucleus
while the red dot around the
outside represents an instance of
the electron. Imagine, as the
electron moves it leaves a trace of
where it was. This collection of
traces quickly begins to resemble
a cloud.
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How to Draw an Atom
First step is to find the element on the periodic table.
 Which row or period is it in? This tell you how many
orbitals it has.
 What is its atomic number? This tells you the number of
protons and electrons it has.
 What is the atomic mass (weight)? Round it off and
subtract the atomic number and you have found the
number of neutrons.
 Record these answers in a table
like this
Check out an example.
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O P E N
-
-
o
o
+
o+o
+
+
o+o
?
-
? ?
?
?-hold places in orbitals
that could have an
electron but do not
have one
- -
2 5 5 6
O P E N
Try to draw carbon, and oxygen
and see how you do.
Ask Mr. Manning when you return to class
on Wednesday for help if you do not
understand.
 Try the review slides that follow.
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Review
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This ancient Greek named the atom.
Democritus
This Greek argued against the existence of atoms.
Aristotle
He was the first chemist and made the first table of elements
John Dalton
In 1897 he published the Plum Pudding Model which put the
electron into the atom.
J.J. Thomson
He put the nucleus into the atom model
Ernest Rutherford
He put the specific regions of electrons called orbitals into the
model.
Niels Bohr
He helped develop the electron Cloud model.
Erwin Schrodinger
Review Continued
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The particle with a positive charge in the nucleus of the atom
Proton
The particle in the nucleus of the atom with no charge
Neutron
The particle with a negative charge that spins at high speed around the
nucleus of the atom
Electron
Particles numbers that are the same as the atomic number
Protons and electrons
Particle number the same as the atomic mass or weight
None
Particle number found by subtracting the atomic number from the atomic
mass whole number part
Neutron
The atomic structure number found by the row or period on which an
element is found
Number of orbitals
The symbol used to represent spaces in an atom where electrons could be
found but are not found
Question mark