The History of the Atom – Theories and Models by Natalie Hector https://padlet.com/dhector0128/josgsg3shln1nh1g A Timeline on Atomic Structure en-us 2022-01-26 16:23:25 UTC 2022-02-06 23:16:02 UTC hello@padlet.com 400 B.C. Democritus dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2013987176 Democritus was a Greek philosopher who lived between 470-380 B.C. He developed the concept of the "atomos", atom, a Greek word for "indivisible". This described the smallest piece of matter.

Interesting Facts:
  • Democritus is believed to have spent his inheritance on travel in order to learn from other cultures' scholars. 
  • He is also known as the "Laughing Philosopher" as he was  described as cheerful while at work. 

REFERENCES:
  1. https://www.worldhistory.org/Democritus/
  2. http://www.abcte.org/files/previews/chemistry/s1_p1.html?nPage=1&nSection=1
  3. https://www.famousscientists.org/democritus/
]]> 2022-01-26 16:42:14 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2013987176 400 B.C. Democritus's Atomic Theory dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2013995223 In 400 B.C. Democritus purposed his Atomic Theory. He stated:
  • All matter is composed of indivisible atoms, which are to small to be seen.
  • There is a void, which is empty space between atoms.
  • Atoms are completely solid.
  • Atoms are homogeneous, with no internal structure.
  • Atoms are different in their size, their shape and their weignt.
  • Atoms are infinite in number, always moving and capable of joining together.

REFERENCES:
  1. https://www.worldhistory.org/Democritus/
  2. http://www.abcte.org/files/previews/chemistry/s1_p1.html?nPage=1&nSection=1
  3. https://www.famousscientists.org/democritus/
]]> 2022-01-26 16:45:32 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2013995223 1803-1808 John Dalton dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2014302562 John Dalton FRS (Fellowship of the Royal Society) was an English chemist, physicist and meteorologist. He is known for introducing the atomic theory into chemistry, and for his research into color blindness, sometimes referred to as "Daltonism".

Interesting Facts:
  • Dalton invented a way to measure the height of mountains. He did this by using a barometer, an instrument for measuring atmospheric pressure.
  • Dalton’s Law of Partial Pressures states that in a mixture, the partial pressures of each gas sum up to form the total pressure. 

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p2.html
  2. https://www.sciencehistory.org/historical-profile/john-dalton
  3. https://www.scienceandindustrymuseum.org.uk/objects-and-stories/john-dalton-atoms-eyesight-and-auroras
  4. https://thehistoryoftheatomicmodel.weebly.com/the-solid-sphere-model.html
]]> 2022-01-26 18:55:53 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2014302562 1803 Solid Sphere Model dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2014378479 The "Solid Sphere Model " is an atomic model proposed by John Dalton in 1803 stating that all objects are made of particles called atoms, and that they are solid spheres that cannot be divided further into smaller particles.

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p2.html
  2. https://www.sciencehistory.org/historical-profile/john-dalton
  3. https://www.scienceandindustrymuseum.org.uk/objects-and-stories/john-dalton-atoms-eyesight-and-auroras
  4. https://thehistoryoftheatomicmodel.weebly.com/the-solid-sphere-model.html
]]> 2022-01-26 19:30:43 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2014378479 1808 Dalton's Atomic Theory dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2014395979 In 1808, Dalton published his Atomic Theory. The main postulates of the theory are: 
  • All matter is made of tiny indivisible particles called atoms, which he imagined as "solid, massy, hard, impenetrable, movable particle(s)".
  • All atoms of a given element are identical in mass and properties. He also noted that the atoms of one element differ from the atoms of all other elements.
  • Compounds are combinations of two or more different types of atoms. 
  • A chemical reaction is a rearrangement of atoms.

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p2.html
  2. https://www.sciencehistory.org/historical-profile/john-dalton
  3. https://www.scienceandindustrymuseum.org.uk/objects-and-stories/john-dalton-atoms-eyesight-and-auroras
  4. https://thehistoryoftheatomicmodel.weebly.com/the-solid-sphere-model.html
]]> 2022-01-26 19:39:47 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2014395979 1808 Periodic Table of Elements dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2015694609 In 1808, Dalton's Periodic Table assigned an "atomic weight" to the atoms of 20 elements which was later published in  A New System of Chemical Philosophy in Volume 1, parts 1.

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p2.html
  2. https://www.sciencehistory.org/historical-profile/john-dalton
  3. https://www.scienceandindustrymuseum.org.uk/objects-and-stories/john-dalton-atoms-eyesight-and-auroras
  4. https://thehistoryoftheatomicmodel.weebly.com/the-solid-sphere-model.html
]]> 2022-01-27 12:07:03 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2015694609 1897-1904 Joseph John Thomson dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2016882210 Joseph John Thomson attended Trinity College at Cambridge, where he would come to head the Cavendish Laboratory. His research in cathode rays led to the discovery of the electron.

Interesting Facts:
  • Thomson won the 1906 Nobel Prize in Physics.
  • Thomson discovered the natural radioactivity of potassium in 1905.
  • In 1906, Thomson demonstrated a hydrogen atom had only a single electron.
  • One of his best-known students was Ernest Rutherford, who succeeded Thomson as Cavendish Professor of Physics.

REFERENCES:
  1. https://nationalmaglab.org/education/magnet-academy/history-of-electricity-magnetism/pioneers/joseph-john-thomson
  2. https://history.aip.org/exhibits/electron/jjthomson.htm
  3. https://www.khanacademy.org/science/chemistry/electronic-structure-of-atoms/history-of-atomic-structure/a/discovery-of-the-electron-and-nucleus
  4. https://courses.lumenlearning.com/cheminter/chapter/thomsons-atomic-model/
]]> 2022-01-27 22:22:06 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2016882210 1897 Discovery Of The Electron dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2016930070 In 1897, Thomson discovered the "electron". He did this by experimenting with "cathode ray tubes". Cathode ray tubes are sealed glass tubes from which most of the air has been evacuated.
The tubes are called cathode ray tubes because the particle beam or "cathode ray" originates at the cathode. The ray can be detected by painting a material known as "phosphors" onto the far end of the tube beyond the anode. The phosphors spark, or emit light, when impacted by the cathode ray.
The results of these experiments helped Thomson determine the "mass-to-charge" ratio of the cathode ray particles.
Thomson repeated his experiments using different metals. He found that the properties of the cathode ray remained constant no matter what cathode material they originated from.

Thomson made the following conclusions:
  • The cathode ray is composed of negatively-charged particles.
  • The particles must exist as part of the atom, since the mass of each particle is only is only ∼1/2000 the mass of a hydrogen atom.
  • These subatomic particles can be found within atoms of all elements.
His cathode ray particles (which he called "corpuscles") were later called "electrons".

REFERENCES:
  1. https://nationalmaglab.org/education/magnet-academy/history-of-electricity-magnetism/pioneers/joseph-john-thomson
  2. https://history.aip.org/exhibits/electron/jjthomson.htm
  3. https://www.khanacademy.org/science/chemistry/electronic-structure-of-atoms/history-of-atomic-structure/a/discovery-of-the-electron-and-nucleus
  4. https://courses.lumenlearning.com/cheminter/chapter/thomsons-atomic-model/ 
]]> 2022-01-27 23:17:54 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2016930070 1904 Plum Pudding Model dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2016964692 Thomson believed that atoms had an overall neutral charge.  He reasoned that there must be a source of positive charge within the atom to counterbalance the negative charge on the electrons.
 In 1904,Thomson proposed that atoms could be described as negative particles floating within a soup of diffuse positive charge.
This model is often called the "Plum Pudding Model" of the atom, since it's description is very similar to plum pudding, an English dessert.

REFERENCES:
  1. https://nationalmaglab.org/education/magnet-academy/history-of-electricity-magnetism/pioneers/joseph-john-thomson
  2. https://history.aip.org/exhibits/electron/jjthomson.htm
  3. https://www.khanacademy.org/science/chemistry/electronic-structure-of-atoms/history-of-atomic-structure/a/discovery-of-the-electron-and-nucleus
  4. https://courses.lumenlearning.com/cheminter/chapter/thomsons-atomic-model/
]]> 2022-01-28 00:02:29 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2016964692 1897 Thomson's Cathode Ray Tube Experiment dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2016985177 Visual Demonstration

REFERENCE:
https://www.youtube.com/watch?v=_nLESblUAHY&t=6s]]> 2022-01-28 00:23:21 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2016985177 1909-1911 Ernest Rutherford dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018706354 Ernest Rutherford was the first man to split an atom, transmuting one element into another. He performed experiments on radioactivity and is regarded as the Father of Nuclear Physics or Father of the Nuclear Age.

Interesting Facts:
  • His work during World War I focused on submarine detection and antisubmarine research.
  • Rutherford was called "Crocodile" by his colleagues. The name referenced the scientist's relentless forward thinking.
  • Rutherford's discoveries were the basis for the design and construction of the larges particle accelerator in the world; the Large Hadron Collider. 

REFERENCES:
  1. https://www.britannica.com/biography/Ernest-Rutherford/McGill-University
  2. https://www.biography.com/scientist/ernest-rutherford
  3. https://chemistrytalk.org/discovering-the-nucleus-rutherfords-gold-foil-experiment/
  4. https://flexbooks.ck12.org/cbook/ck-12-chemistry-flexbook-2.0/section/4.14/primary/lesson/rutherfords-atomic-model-chem/
]]> 2022-01-28 21:53:59 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018706354 1909 Rutherford's Gold Foil Experiment Video dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018751799 Visual Demonstration

REFERENCE:
https://www.youtube.com/watch?v=zUtIrO3fUgg]]> 2022-01-28 23:02:48 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018751799 Denisse "Natalie" Hector-About The Author dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018761982 Denisse "Natalie" Hector was born in China where her mother taught English. Currently she resides in Antipolo, Philippines. Her family includes one brother, two sisters and six dogs. She has travelled to seven southeast asian countries where she experienced different cultures and cuisines and visited many notable landmarks.
Her goals are to pass 8th grade at Miriam College and to pursue a career in either Computer Animation or Computer Programming.
Ms. Hector is now employed at the museum in the Science and Art Department.
Her presentation is to be "showcased" as part of their reopening.

Interesting Facts:
  • Has extensive knowledge of iPhones and iPads. Skilled in using Instagram and Genshin Impact.
  • Wants the Pandemic to end so he can attend face to face classes at Miriam College.
  • The "wallpaper" used in her presentation is the interior of a Nuclear Fission Reactor (cen.acs.org).
]]> 2022-01-28 23:23:21 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018761982 1911 Nuclear Model dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018881172 In 1911, based on his observations from his Gold Foil Experiment, Rutherford proposed the "Nuclear Model", in which an atom consists of a very small, positively charged nucleus surrounded by the negatively charged electrons. Based on the number of alpha particles deflected in his experiment, Rutherford calculated that the nucleus took up a tiny fraction of the volume of the atom.

REFERENCES:
  1. https://www.britannica.com/biography/Ernest-Rutherford/McGill-University
  2. https://www.biography.com/scientist/ernest-rutherford
  3. https://chemistrytalk.org/discovering-the-nucleus-rutherfords-gold-foil-experiment/
  4. https://flexbooks.ck12.org/cbook/ck-12-chemistry-flexbook-2.0/section/4.14/primary/lesson/rutherfords-atomic-model-chem/
]]> 2022-01-29 03:43:29 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018881172 1909 Gold Foil Experiment dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018896606 In the 1909 Gold Foil Experiment, Rutherford fired a thin beam of alpha particles at a very thin sheet of pure gold. He placed a sample of radium (a radioactive metal) inside a lead box with a small pinhole.This would allow detection of the deflected particles.
Rutherford observed while most of the alpha particles were undeflected, a very small percentage (about 1 in 8000 particles) bounced off the gold foil at very large angles. Some were redirected back to the source.

Based on his experimental results, Rutherford made the following conclusions about the structure of the atom:
  • The positive charge must be localized over a very tiny volume of the atom, which also contains most of the atom's mass (nucleus).
  • Since most of the alpha particles passed straight through the gold foil, the atom must be made up of mostly empty space.

REFERENCES:
  1. https://www.britannica.com/biography/Ernest-Rutherford/McGill-University
  2. https://www.biography.com/scientist/ernest-rutherford
  3. https://chemistrytalk.org/discovering-the-nucleus-rutherfords-gold-foil-experiment/
  4. https://flexbooks.ck12.org/cbook/ck-12-chemistry-flexbook-2.0/section/4.14/primary/lesson/rutherfords-atomic-model-chem/
]]> 2022-01-29 04:17:28 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018896606 1913 Niels Bohr dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018927998 Niels Bohr was born in Copenhagen, Denmark, on October 7, 1885. In 1903, he entered Copenhagen University to study physics. He received his Master's degree in Physics in 1909 and his Doctor's degree in 1911. During World War II, Niels Bohr fled Copenhagen to escape Nazis prosecution under Hitler.

 Interesting Facts:
  • He was part of the group of scientists that invented the atomic bomb as part of the Manhattan Project. 
  • He worked on the Manhattan Project under the assumed name of Nicholas Baker for security reasons.
  • As a reward for his hard work, Denmark's Carlsberg Brewery gifted Bohr a home complete with a pipeline that pumped fresh beer directly into his residence.
  • Bohrium is the name of an element named after Bohr.

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p6.html
  2. https://www.livescience.com/32016-niels-bohr-atomic-theory.html
  3. https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Chemistry_-_The_Central_Science_(Brown_et_al.)/06._Electronic_Structure_of_Atoms/6.3%3A_Line_Spectra_and_the_Bohr_Model#:~:text=In%201913%2C%20a%20Danish%20physicist,have%20only%20certain%20allowed%20radii.
  4. https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Book%3A_Introductory_Chemistry_(CK-12)/05%3A_Electrons_in_Atoms/5.06%3A_Bohr's_Atomic_Model
]]> 2022-01-29 05:39:13 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2018927998 1913 Planetary Model dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019070349
Niels Bohr published his "Planetary Model "of Atomic Structure in 1913. His theory suggested:
  • That electrons traveled in orbits around the atom's nucleus.
  • That the chemical properties of the element was largely determined by the number of electrons in the outer orbits.
  • That an electron could drop from a higher-energy orbit to a lower one, emitting a photon (light quantum) of discrete energy.

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p6.html
  2. https://www.livescience.com/32016-niels-bohr-atomic-theory.html
  3. https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Chemistry_-_The_Central_Science_(Brown_et_al.)/06._Electronic_Structure_of_Atoms/6.3%3A_Line_Spectra_and_the_Bohr_Model#:~:text=In%201913%2C%20a%20Danish%20physicist,have%20only%20certain%20allowed%20radii.
  4. https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Book%3A_Introductory_Chemistry_(CK-12)/05%3A_Electrons_in_Atoms/5.06%3A_Bohr's_Atomic_Model
]]> 2022-01-29 11:10:32 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019070349 1913 Bright Line Spectrum Experiment dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019133101 A Bright Light Spectrum is an emission spectrum consisting of bright lines against a dark background.When an electron absorbs sufficient energy it moves to a higher energy level to produce an excited state. Since each element has its own unique electron arrangement, the light that is emitted by the atoms produces an "emission spectrum" that can be used to identify the element.
When an element or ion is heated by a flame or excited by electric current, the excited atoms emit light of a characteristic color. The emitted light can be refracted by a prism, producing spectra with a distinctive striped appearance due to the emission of certain wavelengths of light. In 1913, Bohr tested "Hydrogen".

Bohr hypothesized:
  • Electrons revolve around the nucleus in a fixed circular path termed “orbits” or “shells” or “energy level.”
  • The orbits are termed as “stationary orbit.”
  • Every circular orbit will have a certain amount of fixed energy and these circular orbits were termed "orbital shells". The electrons will not radiate energy as long as they continue to revolve around the nucleus in the fixed orbital shells.
  • The different energy levels are denoted by integers such as n=1 or n=2 or n=3 and so on. These are called as quantum numbers. The range of quantum number may vary and begin from the lowest energy level (nucleus side n=1) to highest energy level.
  • The different energy levels or orbits are represented in two ways such as 1, 2, 3, 4…  or K, L, M, N….. shells.  The lowest energy level of the electron is called the "ground state".
  • The change in energy occurs when the electrons jump from one energy level to other. In an atom, the electrons move from lower to higher energy level by acquiring the required energy. However, when an electron loses energy it moves from higher to lower energy level.

These postulates were the basis for Bohr's "Planetary  Model".

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p6.html
  2. https://www.livescience.com/32016-niels-bohr-atomic-theory.html
  3. https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Chemistry_-_The_Central_Science_(Brown_et_al.)/06._Electronic_Structure_of_Atoms/6.3%3A_Line_Spectra_and_the_Bohr_Model#:~:text=In%201913%2C%20a%20Danish%20physicist,have%20only%20certain%20allowed%20radii.
  4. https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Book%3A_Introductory_Chemistry_(CK-12)/05%3A_Electrons_in_Atoms/5.06%3A_Bohr's_Atomic_Model
]]> 2022-01-29 13:02:18 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019133101 1913 Bohr's Bright Line Spectra Visual Presentation and Explanation dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019158486 Presentation and Explanation

******There is a simulator that you can test several elements to see their spectrum colors.
The website is https://phet.colorado.edu/sims/cheerpj/discharge-lamps/latest/discharge-lamps.html?simulation=discharge-lamps

REFERENCE:
https://www.youtube.com/watch?v=zVQHSBt6BlA&t=1s]]> 2022-01-29 13:43:40 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019158486 1926 Erwin Schrödinger dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019382704 Erwin Schrödinger was an Austrian physicist who worked in the field of quantum theory.  His works were the framework for wave mechanics by formulating the wave equation and matrix mechanics. With his in-depth knowledge of wave mechanics, he originated the physical meaning of wave function. Erwin Schrödinger wrote several books in other fields of physics including electrodynamics, color theory, statistical mechanics and thermodynamics, general relativity, physics of dielectrics and cosmology.

Interesting Facts:
  • His thesis for the Schrödinger equation was written while in a sanatorium, being treated for tuberculosis. 
  • A Moon crater was named after him. Found on the far side of the Moon near the lunar south pole, the Schrödinger crater is the best-preserved impact basin of its kind.
  • He was drafted into World War 1 in 1914, serving with Austro-Hungarian military forces in Italy as an artillery officer.

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p6.html
  2. https://www.physicsoftheuniverse.com/scientists_schrodinger.html
  3. https://byjus.com/jee/schrodinger-wave-equation/
  4. http://www.kentchemistry.com/links/AtomicStructure/schrodinger.htm
  5. https://courses.lumenlearning.com/cheminter/chapter/quantum-mechanical-atomic-model/
  6. https://chemistryqna.com/quantum-mechanical-model/
]]> 2022-01-29 18:43:48 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019382704 1926 Quantum Mechanical Model dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019403121 In 1926, Erwin Schrödinger proposed the "Quantum Mechanical Model "of the atom, which treats electrons as matter waves.

Schrödinger's model concludes that:
  •  Electrons are located in specific energy levels. 
  •  There is no exact path around the nucleus. 
  •  Estimates the probability of finding an electron in a certain positon. 

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p6.html
  2. https://www.physicsoftheuniverse.com/scientists_schrodinger.html
  3. https://byjus.com/jee/schrodinger-wave-equation/
  4. http://www.kentchemistry.com/links/AtomicStructure/schrodinger.htm
  5. https://courses.lumenlearning.com/cheminter/chapter/quantum-mechanical-atomic-model/
  6. https://chemistryqna.com/quantum-mechanical-model/
]]> 2022-01-29 19:13:23 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019403121 1926 Schrödinger Wave Equation dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019460245 Schrödinger Wave Equation is a mathematical expression describing the energy and position of the electron in space and time, taking into account the matter wave nature of the electron inside an atom.

The equation is named after Erwin Schrödinger, who postulated the equation in 1925, and published it in 1926.

The Schrödinger Wave Equation is used to calculate:
  • The form of the wave functions or probability waves that control the motion of some smaller particles. 
  • The equation describes how these waves are influenced by external factors. 
  • The equation makes use of the energy conservation concept that offers details about the behavior of an electron that is attached to the nucleus.
  • The equation helps determine the quantum numbers as well as the orientations and the shape of orbitals where electrons are found in a molecule or an atom. To completely describe an electron in an atom, four quantum numbers are needed: energy (n), angular momentum (ℓ), magnetic moment (mℓ), and spin (ms).

REFERENCES:
  1. http://www.abcte.org/files/previews/chemistry/s1_p6.html
  2. https://www.physicsoftheuniverse.com/scientists_schrodinger.html
  3. https://byjus.com/jee/schrodinger-wave-equation/
  4. http://www.kentchemistry.com/links/AtomicStructure/schrodinger.htm
  5. https://courses.lumenlearning.com/cheminter/chapter/quantum-mechanical-atomic-model/
  6. https://chemistryqna.com/quantum-mechanical-model/
]]> 2022-01-29 20:50:52 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019460245 1926 The Schrödinger Wave Equation and Wavefunctions dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019489221 Video Tutorial

REFERENCE:
https://www.youtube.com/watch?v=Z9Vx-xpgW0g]]> 2022-01-29 21:45:07 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019489221 1932 James Chadwick dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019497683 James Chadwick proved the existence of neutrons - elementary particles without any electrical charge. This discovery contributed to the successful controlled fissioning of Uranium-235, and eventually to the development of the atomic bomb. He was awarded the Hughes Medal of the Royal Society in 1932, and the Nobel Prize for Physics in 1935.

Interesting Facts:
  • He was a POW (Prisoner Of War) during WWI as he was studying with scientists in Berlin, Germany.
  • He was Knighted by the Crown of England in 1945, making him Sir James Chadwick.
  • He was awarded a Nobel prize in Physics in 1935 for his discovery of the neutron. 
  • During WWII he also helped develop the Atomic Bomb. He worked with the US government on the secretive Manhattan Project.

REFERENCES:
  1. https://www.famousscientists.org/james-chadwick/
  2. https://www.aps.org/publications/apsnews/200705/physicshistory.cfm
  3. https://sites.google.com/site/mrjhatomichistory/james-chadwick
  4. https://www.slideserve.com/keefe/each-box-below-illustrates-an-atomic-model-proposed-during-the-course-of-history
  5. https://www.vedantu.com/question-answer/did-james-chadwick-contribute-to-the-atomic-th-class-12-physics-cbse-5feaec3bf391d0241fecf5cd
  6. https://www.slideserve.com/keefe/each-box-below-illustrates-an-atomic-model-proposed-during-the-course-of-history
]]> 2022-01-29 22:03:12 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019497683 Timeline-Discovery Of The Neutron dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019662263 Video examines  the experiments that led up to James Chadwick's identification of the neutron.

REFERENCE:
https://www.youtube.com/watch?v=2bNdMzbIuzw]]> 2022-01-30 06:02:26 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019662263 1932 Discovery Of The Neutron dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019671760  Chadwick's discovery of the "neutron" was based on experiments performed by several scientists.
  • In 1917, Ernest Rutherford found evidence of the existence of a neutrally charged particle within the atomic nucleus.
  •  In 1930, the German physicists Walther Bothe and Herbert Becker shot alpha rays at beryllium (atomic number 4). The beryllium emitted a neutral radiation. Bothe and Becker assumed the neutral radiation was high-energy gamma rays.
  • Frederic and Irene Joliot-Curie, placed a block of paraffin wax in front of the beryllium rays. They observed high-speed protons coming from the paraffin. They knew that gamma rays could eject electrons from metals. They thought the same thing was happening to the protons in the paraffin. 
  • Chadwick said the radiation could not be gamma rays. The law of conservation of energy states that energy can neither be created nor destroyed. Their experiment showed that energy was being created along with the neutral radiation. 
  • Chadwick believed they were neutrons. He set up an experiment to test his hypothesis. Chadwick put a piece of beryllium in a vacuum chamber with some polonium. The polonium emitted alpha rays, which struck the beryllium. When struck, the beryllium emitted the neutral rays.
  • In the path of the rays, Chadwick put a target. When the rays hit the target, they knocked atoms out of it. The atoms, which became electrically charged in the collision, flew into a detector. Chadwick used targets of different elements, measuring the energy needed to eject the atoms of each. Gamma rays could not explain the speed of the atoms. The only plausible explanation for his result was a neutral particle.
  • To prove that the particle was indeed the neutron, Chadwick measured its mass. He could not weigh it directly. Instead he measured everything else in the collision and used that information to calculate the mass. 
In February 1932, Chadwick  published a paper called, “Possible Existence of a Neutron” in the journal Nature. The  neutron had been discovered, and named.

REFERENCES:
  1. https://www.famousscientists.org/james-chadwick/
  2. https://www.aps.org/publications/apsnews/200705/physicshistory.cfm
  3. https://sites.google.com/site/mrjhatomichistory/james-chadwick
  4. https://www.slideserve.com/keefe/each-box-below-illustrates-an-atomic-model-proposed-during-the-course-of-history
  5. https://www.vedantu.com/question-answer/did-james-chadwick-contribute-to-the-atomic-th-class-12-physics-cbse-5feaec3bf391d0241fecf5cd
  6. https://www.slideserve.com/keefe/each-box-below-illustrates-an-atomic-model-proposed-during-the-course-of-history
]]> 2022-01-30 06:29:29 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2019671760 1932 Chadwick's Contribution To Atomic Theory dhector0128 https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2030497247 The results of Chadwick's experiments in 1932 contributed to the development of Atomic Theory:
  • Chadwick found the neutron in atom. The neutron is located in the centre of an atom, along with the protons in the nucleus.
  • They have neither a positive nor a negative charge, but they add the same effect as a proton to the atomic weight.
  • He found that Beryllium emitted a stream of radiation when bombarded by alpha particles. Chadwick stated that the radiation which was produced was composed of particles with a neutral electrical charge and the approximate mass of a proton. 
  • Chadwick was able to explain the existence of isotopes through his discovery of the neutron. Isotopes of the same element have the same number of protons and electrons but differ in the number of neutrons found in their nucleus.

REFERENCES:
  1. https://www.famousscientists.org/james-chadwick/
  2. https://www.aps.org/publications/apsnews/200705/physicshistory.cfm
  3. https://sites.google.com/site/mrjhatomichistory/james-chadwick
  4. https://www.slideserve.com/keefe/each-box-below-illustrates-an-atomic-model-proposed-during-the-course-of-history
  5. https://www.vedantu.com/question-answer/did-james-chadwick-contribute-to-the-atomic-th-class-12-physics-cbse-5feaec3bf391d0241fecf5cd
  6. https://www.slideserve.com/keefe/each-box-below-illustrates-an-atomic-model-proposed-during-the-course-of-history
]]> 2022-02-05 08:53:35 UTC https://padlet.com/dhector0128/josgsg3shln1nh1g/wish/2030497247