Democritus first proposed in 400 BC that matter is made of indivisible particles called atoms. This idea was ignored for over 2000 years. In the early 1800s, Dalton proposed that atoms are small, hard spheres that make up elements. Thomson's 1897 discovery of the electron led to his "plum pudding" model of atoms with positive charge and embedded electrons. Rutherford's 1909 gold foil experiment showed that atoms have a small, dense nucleus surrounded by empty space. Bohr's 1913 model depicted electrons orbiting the nucleus in fixed energy levels like planets around the sun. Modern atomic theory describes electrons as existing in probabilistic "clouds" or orbitals around the nucleus based on quantum mechanics.
Planck's Quantum Theory and Discovery of X-raysSidra Javed
Planck's quantum theory
Discovery of X-rays and explanation of production of X-rays, relation between atomic number and frequency of X-rays, application and uses of X-rays.
Planck's Quantum Theory and Discovery of X-raysSidra Javed
Planck's quantum theory
Discovery of X-rays and explanation of production of X-rays, relation between atomic number and frequency of X-rays, application and uses of X-rays.
Bohr's Theory is based on an early model of atom where electrons travel round the nucleus in a discrete stable numbers of orbit determined by Quantum conditions. This is an extension of Rutherford Model of atom.
Bohr's Theory is based on an early model of atom where electrons travel round the nucleus in a discrete stable numbers of orbit determined by Quantum conditions. This is an extension of Rutherford Model of atom.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
3. Atomic Models
This model of the
atom may look
familiar to you. This is
the Bohr model. In
this model, the
nucleus is orbited by
electrons, which are
in different energy
levels.
A model uses familiar ideas to
explain unfamiliar facts
observed in nature.
A model can be changed as
new information is collected.
4. The atomic
model has
changed
throughout the
centuries,
starting in 400
BC, when it
looked like a
billiard ball →
5. Who are these men?
In this lesson, we’ll learn
about the men whose quests
for knowledge about the
fundamental nature of the
universe helped define our
views.
6. Democritus
This is the Greek
philosopher Democritus
who began the search for
a description of matter
more than 2400 years
ago.
He asked: Could
matter be divided into
smaller and smaller
pieces forever, or was
there a limit to the
number of times a
piece of matter could
be divided?
400 BC
7. Atomos
His theory: Matter could
not be divided into
smaller and smaller
pieces forever, eventually
the smallest possible
piece would be obtained.
This piece would be
indivisible.
He named the smallest
piece of matter “atomos,”
meaning “not to be cut.”
8. Atomos
To Democritus, atoms
were small, hard
particles that were all
made of the same
material but were
different shapes and
sizes.
Atoms were infinite in
number, always
moving and capable
of joining together.
9. This theory was ignored and
forgotten for more than 2000
years!
10. Why?
The eminent
philosophers
of the time,
Aristotle and
Plato, had a
more
respected,
(and
ultimately
wrong) theory.
Aristotle and Plato favored the earth, fire, air
and water approach to the nature of matter.
Their ideas held sway because of their
eminence as philosophers. The atomos idea
was buried for approximately 2000 years.
11.
12. JOHN DALTON
Early 1800’s
Thought atoms were smooth, hard balls
that could not be broken into smaller
pieces.
All elements are made of atoms.
All atoms of the same element are
exactly alike and have same mass.
An atom of one element cannot be
changed into an atom of a different
element.
Atoms cannot be created nor destroyed,
only rearranged.
Compounds are made from atoms of
14. The “Billiard Ball” Model
proposed by John Dalton in 1804
this theory proposed that matter was composed of small,
spherical particles
but evidence was later gathered that matter was composed of
even smaller bits
15. J.J. THOMSON
1897
An atom consists of negative charges scattered
throughout a ball of positive charges.
17. Thomson: “Plum Pudding” or
“Chocolate Chip Cookie” Model
using available data on the atom, J.J. Thomson
came up with the idea of having charges embedded
with Dalton’s Billiard Balls
Also used cathode ray experiment to discover the
existance of the electron
positive
(evenly distributed)
“dough”
part
negative
“chocolate”
note: this model kept Dalton’s key ideas intact
18. Thomson Model
The discovery of the electron by J. J. Thomson showed that
atoms did have some kind of internal structure.
The Thomson model of the atom described the atom as a
"pudding" of positive charge, with negatively charged
electrons embedded
19. Discovery of the Electron
In 1897, J.J. Thomson used a cathode ray
tube to deduce the presence of a negatively
charged particle: the electron
Click on me:
http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swf
20. Conclusions from the Study of the
Electron:
A. Cathode rays have identical properties
regardless of the element used to produce
them. All elements must contain identically
charged electrons.
B. Atoms are neutral, so there must be
positive particles in the atom to balance the
negative charge of the electrons
C. Electrons have so little mass that atoms
must contain other particles that account
for most of the mass
21. J.J. Thomson’s Plum Pudding Model
Positively
charged
“pudding”
Negatively
charged particles
later named
electrons
22. ERNEST RUTHERFORD
1911
Rutherford was a student of Thomson.
Positive charge (protons) is located in the center of
the atom.
Center is called the nucleus.
Almost all of the atom’s mass is located in the
nucleus.
Atom is mostly empty space with the electrons
moving around the nucleus.
24. Nuclear Model
Ernest Rutherford discovered a huge flaw in
the previous concept of the atom during his
now famous gold foil experiment
25. Gold Foil Experiment
• Particles shot through thin sheet of gold
• Most shots went straight through
• A small amount were deflected
• Hence… The atoms must be made of mostly empty space with a
small dense nucleus
26. If previous models were correct alpha particles would
have passed straight through the the gold
Further explanation of Nuclear Model
27. Rutherford found that most (99%) of the alpha particles that he shot at the gold went
straight through
From these experiments Rutherford concluded that the atom had a dense positive core,
with the rest composed of mostly empty space with the occasional negatively charged
electron
Nuclear Model
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note: this model completely changed the definition of atom
28. Rutherford’s Findings
#1 The nucleus is small
#2 The nucleus is dense
#3 The nucleus is positively
charged
* Most of the particles passed right through
* A few particles were deflected
* VERY FEW were greatly deflected
“Like howitzer shells bouncing
off of tissue paper!”
Conclusions:
29. NEILS BOHR
1913
Bohr was a student of Thomson & Rutherford
Electrons could only have specific amounts of
energy, leading them to move in certain orbits.
This model is also compared to planets orbiting in
the solar system.
31. Bohr Model
Niels Bohr proposed that electrons revolve
around the central positive nucleus (like
planets in the solar system)
negative electrons
3 positive protons
32. Bohr Model
Bohr also suggested that the electrons can only
revolve in certain orbits, or at certain energy levels
(ie, the energy levels are quantized)
no energy level in between steps
33. The Modern Atom
The modern atom is further defined by the works of these
scientists:
Max Plank
de Broglie
Albert Einstein
James Chadwick
Heisenberg
Erwin Schrodinger
Electrons do not orbit the
nucleus like planets, rather
they can be anywhere in a
cloudlike region around the
nucleus.
Electrons of the same energy
are in the same energy level.
34. Max Plank
Germany, 1918
Energy is gained or lost in discrete
“packets” called quanta
Calculated the amount of energy
and determined that it is a constant
Plank’s Constant
hv
Founded quantum mechanics
theory
He was also an accomplished
musician!
35. •Father of Quantum Physics
•Electrons absorb and emit
energy in discrete “packets”
called quanta
Max Plank
36. de Broglie, 1924
Electrons move like waves and so have
properties of waves.
Albert Einstein
Einstein was simultaneously working on the
photoelectric effect, the theory of relativity
and the energy-mass relationship.
37. JAMES CHADWICK
1932
Found that the atom has a particle that was
electrically neutral (neutron).
38. MODERN SCIENTISTS / JAMES CHADWICK
Atomic Model
Object used to represent
theory
39. Heisenberg and Schrodinger
Found that Electrons live in fuzzy
regions or “clouds” not distinct
orbits
Improved on Bohr’s findings
Electron location can not be
predicted
Quantum Mechanical Model
40. Heisenberg, 1925
Heisenberg proposed that it is not possible to
know the position and momentum of an
electron at the same time.
Heisenberg Uncertainty Principle
42. Quantum Mechanical Model
the current understanding of the atom is based on
Quantum Mechanics
this model sees the electrons not as individual
particles, but as behaving like a cloud - the electron
can be “anywhere” in a certain energy level
Remember back to CPE with electrons behaving
like bees in a beehive
43. Quantum Mechanical Model
electrons can be found
anywhere in these “shells”
note: the electrons
are still quantized
no electrons can
be found here
44. FYI: Chemistry
most things we do can be explained using
Dalton’s and/or Bohr’s model
the Quantum Mechanical model, although
most accurate, is complex even at a
university level (conceptually and
mathematically)
Click on me or copy and paste into browser:
http://www.hyperhistory.com/online_n2/people_n2/science_n2/atomic_theory.html
48. The Wave Model
Today’s atomic model is
based on the principles of
wave mechanics.
According to the theory of
wave mechanics,
electrons do not move
about an atom in a definite
path, like the planets
around the sun.
49. The Wave Model
In fact, it is impossible to
determine the exact location of an
electron. The probable location of
an electron is based on how much
energy the electron has.
According to the modern atomic
model, at atom has a small
positively charged nucleus
surrounded by a large region in
which there are enough electrons
to make an atom neutral.
50. Electron Cloud:
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.
51. Electron Cloud:
Depending on their energy they are locked into a certain area in
the cloud.
Electrons with the lowest energy are found in the energy
level closest to the nucleus
Electrons with the highest energy are found in the outermost
energy levels, farther from the nucleus.
52. Indivisible Electron Nucleus Orbit Electron
Cloud
Greek X
Dalton X
Thomson X
Rutherford X X
Bohr X X X
Wave X X X
53. Models of the Atom
Dalton’s model
(1803)
Thomson’s plum-pudding
model (1897)
Rutherford’s model
(1909)
Bohr’s model
(1913)
Charge-cloud model
(present)
Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 125
Greek model
(400 B.C.)
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"In science, a wrong theory can be valuable and better than no theory at all."
- Sir William L. Bragg
54. Models of the Atom
Dalton’s model
(1803)
Thomson’s plum-pudding
model (1897)
Rutherford’s model
(1909)
Bohr’s model
(1913)
Charge-cloud model
(present)
Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 125
Greek model
(400 B.C.)
1800 1805 ..................... 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945
1803 John Dalton
pictures atoms as
tiny, indestructible
particles, with no
internal structure.
1897 J.J. Thomson, a British
scientist, discovers the electron,
leading to his "plum-pudding"
model. He pictures electrons
embedded in a sphere of
positive electric charge.
1904 Hantaro Nagaoka, a
Japanese physicist, suggests
that an atom has a central
nucleus. Electrons move in
orbits like the rings around Saturn.
1911 New Zealander
Ernest Rutherford states
that an atom has a dense,
positively charged nucleus.
Electrons move randomly in
the space around the nucleus.
1913 In Niels Bohr's
model, the electrons move
in spherical orbits at fixed
distances from the nucleus.
1924 Frenchman Louis
de Broglie proposes that
moving particles like electrons
have some properties of waves.
Within a few years evidence is
collected to support his idea.
1926 Erwin Schrödinger
develops mathematical
equations to describe the
motion of electrons in
atoms. His work leads to
the electron cloud model.
1932 James
Chadwick, a British
physicist, confirms the
existence of neutrons,
which have no charge.
Atomic nuclei contain
neutrons and positively
charged protons.
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