This document provides an overview of the history and development of the atomic model. It discusses early Greek philosophers like Democritus who proposed that all matter is made up of tiny indivisible particles called atoms. The document then outlines major scientists and their contributions to understanding atomic structure, including Dalton's atomic theory, Thomson's plum pudding model, Rutherford's gold foil experiment, Bohr's planetary model, and Schrodinger's wave mechanic model. It concludes by explaining current atomic structure including subatomic particles like protons, neutrons, and electrons as well as isotopes, ions, and how atomic number and mass relate to the periodic table.

1. Today in Science
You will Need:
1)Pencil, Colored Pencils, Highlighters or
Markers
2)Power Notes – Atomic Structure– 1
page 2 sides -Bookshelf

2. 1.MANAGER– Log in to LearningPoint –
Lead discussion
2. MATERIALS MANAGER– Organize
Table Box
3. TIMER/DESIGNER– “Highlighting
Patrol”
4.ORAL PRESENTER– Communicator,
Asks Questions for the group

3. Topic:
Power Notes- Atomic
Structure
Name
Date
Period
• The concept of “atoms” is believed to
have originated in ancient Greece
with Democritus supporting the idea
that all matter is made up of tiny
particles. It has taken several
hundred years to understand what
we know about the atom today. .
Do we understand
everything????
*NOT EVEN CLOSE!

4. Democritus 400 BC
Greece - stated that
all matter is made up
of atoms. He also
stated that atoms
are eternal and
invisible and so
small that they can’t
be divided, and they
entirely fill up the
space they’re in
Lavoisier 1789
France - provided the
formula for the
conservation of
matter in chemical
reactions, and also
distinguished
between an element
and a compound
• 1st idea of “atoms”
• Believed all matter is made
up of tiny particles separated
by space
• Named particles “atomos”
which means indivisible.
• Founder of modern
chemistry
• 1st carefully controlled
experiments providing
evidence to the Law of
Conservation of Mass

5. Dalton 1766-1844
England - formed the 1st atomic theory,
which states that all matter is composed
of tiny, indestructible particles called
atoms that are all alike and have the
same atomic weight.
1st MODERN Atomic Theory
1. All matter made up of tiny
indivisible particles called
atoms
2. Atoms of the same element
have identical properties
3. Atoms of different elements
have different properties
4. Atoms combine in a specific
ratio to form compounds
5. A specific compound is
always made up of atoms in
a specific proportion.

6. Thomson 1897
Plum Pudding Model
1.Negative particles scrambled
into the “dough” of the positive
particles.
England - discovered
the electron and
developed the plumpudding model of the
atom.
Rutherford 1898
England - used the
results of his gold-foil
experiment to state that
all the mass of an
atom was in a small
positively-charged ball
at the center of the
atom.
Gold Foil Experiment
1.Atoms are mostly empty
space
2.All the Mass of an atom is in
the positively charged ball in the
center of the structure.

7. Bohr 1922
Denmark - stated that
the electrons moved
around the nucleus in
successively large
orbits. He also
presented the Bohr
atomic model which
stated that atoms
absorb or emit
radiation only when the
electrons abruptly
jump between allowed,
or stationary, states.
Schrödinger (Schroedinger
Austria - introduced the
)1930
Shroedinger Equation, a
wave equation that
describes the form of
the probability waves
that govern the motion of
small particles and how
these waves are altered
by external influences.
“Planetary” atom model
1.Believed the atom structure was like our
solar system
2. Nucleus in the middle like the sun and
the electrons orbiting like the planets.
Wave Mechanic Model
1.Planetary model was too specific
2.Rather: electrons vibrate around the
outside of the nucleus- can only
predict where they are most like to be
3.QUARKS – protons, neutrons and
electrons made up of some of these
smaller particles.
4.http://library.thinkquest.org/05aug/01087/quarks.html

8. Basic Atomic Structure
Today scientists agree on the
three basic subatomic particles
that make up all atoms.
Bohr Model for Lithium
Electron = 3
(not to scale)
Make sure to
include these
question next to
your model
P= 3 +
N=3 0
Answer
s
Where is most of the mass in the
Atom?
NUCLEUS
Where is most of the volume in the
Atom?
Outside the Nucleus; Electron
Cloud

9. Nucleus
•
•
•
No need to include
words…just illustration
Electron
•
•
•
•
Contains protons(+) and
Neutrons (0)
Holds most of the mass of
the atom
Very small compared to the
entire size of the atom
Most dense part of the atom
Negatively charged
subatomic particle
Found outside the nucleus in
the electron cloud
Smallest particle; mass =
1/1836th of the atom

10. Proton
•
•
•
•
Neutron
•
•
•
•
•
•
Positively charged subatomic particle,
Found in the nucleus
Mass = 1 amu (atomic mass unit)
# of protons in an atom IDENTIFIES the
atom (which element)
# of protons in the nucleus of an atom
called the atomic number
Zero charge
Mass = 1 amu
Do NOT affect the identity of the atom
Found in the nucleus
Same atom of an element can have
varying amounts of neutrons (isotope)
Adding the total number of protons &
neutrons = Atomic Mass Number
http://www.sawyerscience.com/Units/unit2/atoms_compounds.html

11. 1.
Atomic Mass on the Periodic Table
represents a “weighted average” of the
mass of all the naturally occurring
ISOTOPES of each element. (based on
mass & abundance of each isotope.)
Atomic Number
1. Number of PROTONS (Unique
to each element)
2. Number of ELECTRONS (IF
Atom is NEUTRAL)
2. Chemical Symbol
1. Abbreviation of element
(some from LATIN name)
3. Element Name
1. Full name provided below
symbol
4. Atomic Mass Number
1. Sum of the particles in the
nucleus
2. Represents total count of
protons and neutrons
3. Positively charged because
neutrons have no charge and
protons are positive

12. All atoms found on the •
Periodic Table are
NEUTRAL– same # of protons(+)
and # of electrons(-)
•
Atoms of the same element with
same number of protons and
different number of neutrons.
Isotope
Hydrogen has 3 natural
occurring ISOTOPES:
Protium, Deuterium and
Tritium
All ISOTOPES of Hydrogen are neutral because they have 1
electron as well. Make sure to include the electron in your
illustration. (Did you put the electron in the right place?)

13. IONS
•
•
When atoms gain or lose electrons
they become charged. (number of
protons (+) and electrons (-)
particles are NOT EQUAL)
Atoms that do not have equal
amounts of protons (+) and
electrons (-) particles are called
IONS
Draw atoms of hydrogen that are charged because
of the UNEQUAL amounts of protons and
electrons.
Review
REVIEW & REFLECT
Short answer, no complete sentences. All answers
are located in your notes.
+
-
On ALL pages – Please do
this with a colored pen,
pencil or marker.

14. Homework
1)None Unless you owe me
something (We will continue working on
Monday and Tuesday of next week)
2)Have a good weekend!
Do You see HOW the periodic table and
the Atomic Structure are RELATED?