History of Atoms

Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre

I am Eugen Goldstein! I
discovered the idea
about the positively
charged particle called
“proton”.

What is an atom?
 The smallest particle of an element.
 The smallest amount of a substance
that can take part in any chemical
reaction.

He is a Greek
Philosopher who began to search
for a description of matter.
•He named the smallest piece of
matter: “ATOMOS” meaning “not
to be cut”.
DEMOCRITUS

They were small, hard
particles that were all made of
the same material but were
different shapes and sizes.
This piece is indivisible.

DEMOCRITUS

JOHN
DALTON

In the early 1800s,John Dalton
(English Chemist) performed a number of
experiments that eventually led to the
acceptance of the idea of atoms.
He deduced that all elements are
composed of atoms.
JOHN DALTON

Atoms of the same element are
exactly alike.
Atoms of different elements are
different.
Compounds are formed by the
joining of atoms of two or more
elements.

JOHN DALTON

JOSEPH JOHN
THOMSON
I introduced the idea
about the negatively
charged particle called
“electron”.

In 1897, J.J. Thomson, an
English Scientist, provided the first hint
that an atom is made of even smaller
particles.
He proposed a model of the atom
that is sometimes called “Plum
Pudding” Model.
JOSEPH JOHN
THOMSON

Atoms were made from
positively charged substance with
negatively charged electrons
scattered about, like raisins in a
pudding.

PLUM
PUDDING
ATOMIC
MODEL

ERNEST
RUTHERFORD

In 1908, E. Rutherford, an English
Physicist, was hand at work on an experiment.
He reasoned that all atoms that are positively
charged particles were contained in the nucleus.
Negatively charged particles were scattered
outside the nucleus around the atoms edge.
ERNEST
RUTHERFORD

NIELS
BOHR

In 1913, N. Bohr, a Danish Scientist,
proposed an improvement.
He placed each electron in an specific energy level.
Electrons move in definite orbits around the
nucleus, much like planet circles the sun. These
orbits, or energy levels are located at certain
distances from the nucleus.
NIEL BOHR

NIEL BOHR

ARNOLD
SOMMERFELD

A. Sommerfeld, a brilliant
German Physicist, modified Niel Bohr’s
atomic theory to include elliptical orbits.
Electrons are moving around the nucleus.
Assumed that orbits doesn’t have to be
spherical but can also be elliptical
ARNOLD
SOMMERFELD

ERWIN
SCHRODINGER

E. Schrodinger, a Physicist and a
Biologist, was considered the Father of
Quantum Mechanics
Today’s atomic model is based on the
principles of wave mechanics.
Electrons do not move around an atom in a
definite path like the planets around the sun.
ERWIN
SCHRODINGER

A space in which electrons are likely to be
found.
Electrons whirl about the nucleus billions of
times in one second.
They are not moving around in random
patterns.
Location of electrons depends upon how
much energy the electron has.

CATEGORY 4 3 2 1
Illustration
The illustration
clearly
communicates the
main idea
The illustration
communicates
some of the
important ideas
The illustration
indirectly
communicates the
idea
The illustration
does not
sufficiently
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idea
Creativity and
Originality
The illustration
reflects an
exceptional degree
of student ingenuity
in their output
Most of the
illustration reflects
student ingenuity in
their output
The illustration was
made by the
student but were
copied from the
ideas of others
The illustration was
not from their own
ideas.
Accuracy and
Relevance of the
Content
The illustration is
accurate and
related to the topic
Most of the
illustration is
accurate and
Some of the
illustration is
accurate and
The illustration is
neither accurate
nor related to the
topic
Required Elements
The illustration
includes all
required elements
as well as additional
information
The illustration
includes all
required elements
The illustration
includes few
required elements
Required elements
are missing
Rubric:

1.He proposed the “Plum Pudding
Model”.
A. Ernest Rutherford
B. Niel Bohr
C. John Joseph Thomson

2. It is a Greek word, means “not
to be cut”
A. Atomos C. Atonos
B. Atamos

3. He proposed quantum
mechanics.
A. John Dalton
B. Erwin Schrodinger
C. John Dalton

4. His theory states that
electrons are moving around the
orbits.
A. Ernest Rutherford
B. Niel Bohr
C. Democritus

5. This is the atomic model theory
of Arnold Sommerfeld.
A. Atoms are moving around
elliptical orbits
B. Electrons are contained in the
nucleus
C. Electrons has no definite location

Give the importance
of the development of atoms
in today’s generation.

References:
LM pages 81 -82
TG pages 97 – 98
https://www.youtube.com/watch?v=7MU
A_yL5GDo

History of Atoms

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