際際滷

際際滷Share a Scribd company logo
The Atom
- Are the building blocks of matter that
make up everything that we encounter
every day.
- The basic unit of matter
- Are the smallest individual part of an element
and it consists of subatomic particles such as
protons, electrons and neutrons.
TIMELINE OF ATOMIC
NATURE
He proposed that all substances are composed
of four elements such as air, earth, fire and
water in different proportion.
fire
air
water
earth
Aristotle
322  384 BC
Empedocles divided matter into
four elements such as air, earth, fire
and water.
Approximately
450 BC
 Democritus and Leucippus 
proposed that everything is
composed of small bit of matter
that is indivisible and call it atom
(atomos  indivisible)
500 BC
 Lavoisier clarified the concept of an
element as a simple substance that
could not be broken down by any
known method of chemical analysis,
and he devised a theory of the
formation of chemical compounds from
elements.
1777
 Coulomb explained that like fluids
repel and unlike attract. This was
important in the development of the
theory of absolute measurement, and
had a great impact on electrical
potential.
1780
(The Solid Sphere Model)
 Billiard Ball Model - small solid
sphere
 Developed notion of
conservation of mass and that
atoms combine in specific
ratios
Daltons Atomic Theory1803
The postulates of this
theory are the ff;
1. All matter is composed of extremely
small, indivisible, indestructible
particles called atoms.
2. All atoms of each element are exactly
alike but they differ from atoms of
the other elements. The atoms of
different elements have different
mass and properties.
The postulates of this
theory are the ff;
3. When atoms of different elements
combine to form a compound, the
constituent atoms are always present in
the same fixed numerical ratio.
The postulates of this
theory are the ff;
4. A chemical reaction involves a
rearrangement of atoms. No atom is
created or destroyed.
Sir William Crookes
- constructed the forerunner of the
modern television picture tube in the
1870s to investigate the properties of
cathode rays.
- Crookes tube  a vacuum discharge
tube
1870
Wilhelm Roentgen
- discovered X-ray by observing the
fluorescence they produced.
1896
 J.J. Thomson
 Plum Pudding Model - positive and
negative particles dispersed
throughout the atom
 Used Cathode Ray tubes to
discover the electron - first
subatomic particle discovered!
1898
Cathode Ray Tube
 A tube that contains a stream of
electrons going from a negative disk
(cathode) to a positive disk.
 Deflected stream showed that
electrons are negative.
Rutherford
 Nuclear Model of an atom
 Discovered dense positively charged
nucleus of the atom while working with
alpha particles
 Gold Foil Experiment
 Neils Bohr -
 Planetary Model of an Atom
 Electrons travel in specific,
circular orbits
Neils Bohr and Arnold Sommerfeld
- Arnold Sommerfeld improved
Bohrs model and introduced the
concept of elliptical orbit.

More Related Content

The Atom

  • 1. The Atom - Are the building blocks of matter that make up everything that we encounter every day. - The basic unit of matter - Are the smallest individual part of an element and it consists of subatomic particles such as protons, electrons and neutrons.
  • 2. TIMELINE OF ATOMIC NATURE He proposed that all substances are composed of four elements such as air, earth, fire and water in different proportion. fire air water earth Aristotle 322 384 BC
  • 3. Empedocles divided matter into four elements such as air, earth, fire and water. Approximately 450 BC
  • 4. Democritus and Leucippus proposed that everything is composed of small bit of matter that is indivisible and call it atom (atomos indivisible) 500 BC
  • 5. Lavoisier clarified the concept of an element as a simple substance that could not be broken down by any known method of chemical analysis, and he devised a theory of the formation of chemical compounds from elements. 1777
  • 6. Coulomb explained that like fluids repel and unlike attract. This was important in the development of the theory of absolute measurement, and had a great impact on electrical potential. 1780
  • 7. (The Solid Sphere Model) Billiard Ball Model - small solid sphere Developed notion of conservation of mass and that atoms combine in specific ratios Daltons Atomic Theory1803
  • 8. The postulates of this theory are the ff; 1. All matter is composed of extremely small, indivisible, indestructible particles called atoms. 2. All atoms of each element are exactly alike but they differ from atoms of the other elements. The atoms of different elements have different mass and properties.
  • 9. The postulates of this theory are the ff; 3. When atoms of different elements combine to form a compound, the constituent atoms are always present in the same fixed numerical ratio.
  • 10. The postulates of this theory are the ff; 4. A chemical reaction involves a rearrangement of atoms. No atom is created or destroyed.
  • 11. Sir William Crookes - constructed the forerunner of the modern television picture tube in the 1870s to investigate the properties of cathode rays. - Crookes tube a vacuum discharge tube 1870
  • 12. Wilhelm Roentgen - discovered X-ray by observing the fluorescence they produced. 1896
  • 13. J.J. Thomson Plum Pudding Model - positive and negative particles dispersed throughout the atom Used Cathode Ray tubes to discover the electron - first subatomic particle discovered! 1898
  • 14. Cathode Ray Tube A tube that contains a stream of electrons going from a negative disk (cathode) to a positive disk. Deflected stream showed that electrons are negative.
  • 15. Rutherford Nuclear Model of an atom Discovered dense positively charged nucleus of the atom while working with alpha particles Gold Foil Experiment
  • 16. Neils Bohr - Planetary Model of an Atom Electrons travel in specific, circular orbits Neils Bohr and Arnold Sommerfeld - Arnold Sommerfeld improved Bohrs model and introduced the concept of elliptical orbit.