https://padlet.com/amdlpied/tjnopzrc7pq65dol en-us 2023-03-29 15:51:59 UTC 2025-09-24 10:14:38 UTC hello@padlet.com amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538516608 Democritus a greek philosopher that stated that "all things were made up of stuffs small particles". He called this particles "Atoms". He believed they were  uniform, solid, hard, incompressible, and indestructible. He also said that atoms are eternal and motion too. Experiment: The experiment he used to prove this theory was that he broke a seashell into two pieces, and with this he just concluded that those two pieces were composed of the same substance. This happened around in 400 B.C 



]]> 2023-03-30 14:42:34 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538516608 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538517023 This is the graphic representation of his concept of particles. He believed that water was created out of water particles. Same with iron and everything else. ]]> 2023-03-30 14:42:51 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538517023 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538620339 Aristotle disagreed with Democritus theory. Instead, he stated that everything was composed of four elements: earth, air, fire, and water. Even thought Democritus's theory was better explained, Aristotle was more influential, so his ideas prevailed.
Sources:
Britannica. (n/d). Development of atomic theory. Recovered from https://www.britannica.com/science/atom/Development-of-atomic-theory
Libretext. (2020). Early Ideas about the Building Blocks of Matter. Recovered from https://chem.libretexts.org/Courses/Rutgers_University/Chem_160%3A_General_Chemistry/01%3A_Atoms/1.04%3A_Early_Ideas_about_the_Building_Blocks_of_Matter#:~:text=Aristotle%20disagreed%20with%20Democritus%20and,influential%2C%20so%20his%20ideas%20prevailed.]]> 2023-03-30 15:51:52 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538620339 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538693056 Lavoiser is considered as the father of modern chemistry. He established the law of conservation of mass. He also determined that combustion and respiration are caused by chemical reactions with an element he called "oxygen". His work was the base for the study of the first breakthrought about chemical reactions (1772 and 1794). ]]> 2023-03-30 16:48:54 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538693056 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538694168 Joseph was a French Chemist that discovered the law of constant proportion on 1797 and he stated the law as "A chemical compound always contains the same elements combined together in the same proportion by mass". Experiment: The experiment he used to prove this law was that he studied cooper carbonate, two tin dioxides and two iron sulfides. He made this by making artificial cooper and comparing it with the natural cooper carbonate. With this he proved that each of them had the same proportion of weights between the other tree other elements he involved


]]> 2023-03-30 16:49:53 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538694168 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538713674 This is a graphic representation of the law about defined proportions. For example in this image it is represented by saying that 4 hydrogens and 2 oxygens are the same as 2 H2Os]]> 2023-03-30 17:06:21 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538713674 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538721080 He stated the theory of conservation of mass (cant be destroyed nor created). He made 5 postulates: all matter consists of indivisible particles called atoms, atoms of the same element are similar in shape and mass, but differ from the atoms of other elements, atoms cannot be created or destroyed, atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms, atoms of same element can combine in more than one ratio to form two or more compounds and the atom is the smallest unit of matter that can take part in a chemical reaction. He thought that the atoms were solid, hard spheres]]> 2023-03-30 17:11:41 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538721080 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538727801 In 1789 he created the law of conservation of matter. His law states that "mass can't be neither created nor destroyed in chemical reactions". Experiment: He tested this theory by  placing a burning candle inside a sealed glass jar. When the candle burned down, the weight was the same.  This confirmed his theory.
Sources:
Sterner, R. (2011). The Conservation of Mass. Recovered from https://www.nature.com/scitable/knowledge/library/the-conservation-of-mass-17395478/#:~:text=The%20Law%20of%20Conservation%20of%20Mass%20dates%20from%20Antoine%20Lavoisier's,the%20end%20of%20the%20reaction.
Vr LAB academy. (n/d). Experiments that Changed the World: The Law of Mass Conservation. Recovered from https://www.vrlabacademy.com/NewsDetail/25/Experiments-that-Changed-the-World--The-Law-of-Mass-Conservation-.html#:~:text=One%20of%20Lavoisier's%20experiments%20entailed,thereby%20proving%20his%20pioneering%20theory.
Science History Institute. (2017). Antoine-Laurent Lavoisier. Recovered from https://www.sciencehistory.org/historical-profile/antoine-laurent-lavoisier#:~:text=Antoine%2DLaurent%20Lavoisier%2C%20a%20meticulous,nomenclature%2C%20among%20many%20other%20accomplishments.]]> 2023-03-30 17:17:15 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538727801 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538774872 The law "When two elements combine with each other to form two or more compounds, the ratios of the masses of one element that combines with the fixed mass of the other are simple whole numbers"]]> 2023-03-30 17:55:22 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538774872 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538778022 Dimitri Mendeleev created the first periodic table. In february of 1869. He created  the framework that became the periodic table we use now. He left spaces for elements that had yet to be discovered.]]> 2023-03-30 17:57:46 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538778022 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538800503 In Mendeleev's periodic table the elements were from left to right across each row, arranged in order of increasing atomic weigh.  He realized that if he put 8 elements in each row and then continue doing the same on the next row, the columns would have similar properties. He called this columns groups.
 
Source: Ck-12. (2021). Mendeleev's Periodic Table. Recovered from https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook-2.0/section/4.1/primary/lesson/mendeleevs-periodic-table-ms-ps/]]> 2023-03-30 18:15:51 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538800503 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538804034 He created one of the most important experiments to prove the electron charge in 1909. ]]> 2023-03-30 18:18:30 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538804034 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538833421 In his experiment a closed chamber with  transparent sides is fitted with two parallel metal plates, that gets a positive or negative charge when an electric current is applied.
1. At the begginning, an atomizer drops a  fine mist of oil droplets into the upper part of the chamber.
2. Because of gravity and air resistance some oil droplets fall through a hole in the metal plates.
3. In a moment, the space between the metal plates will be ionized by radiation.
4. Electrons from the air attach themselves to the falling oil droplets. This causes them to get a negative charge.
5. A light source set at right angles to a viewing microscope, illuminates de oil dropplets and they seem like shiny stars as they fall.
6. By varying the strength of the electric field the charge over an oil droplet was calculated. And it always came out as the value 'e.
This experiment offered proof that electric charges exists in natural units.

Source: Britannica. (n/d). Millikan oil-drop experiment. Recovered from https://www.britannica.com/science/Millikan-oil-drop-experiment]]> 2023-03-30 18:44:29 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538833421 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538847342 Erwin Schrödinger was an Austrian Scientific that contribute to the wave theory of matter. In 1926 he formulate formulated a wave equation that accurately calculated the energy levels of electrons in atoms. He showed that the hydrogens atoms energy levels that appear in Bohr atomic model could be calculate with the Schrödinger equation. Also he discover that  his wavelike aspect and Heisenberg corpuscular aspect were the same thing but only said in other way. ]]> 2023-03-30 18:56:52 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538847342 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538855047 Finally he formulate the the quantum mechanical model of the atom. And in 1937 he formulate the experiment of the Cat of Schrödinger, in which he illustrate the differences between interaction and measurement in the field of quantum mechanics by exemplifying both unpredictability and the so-called superposition, the possibility that two opposite states exist simultaneously.
Sources:
Bernstein, J. (2023) Erwin Schrödinger. Britannica. Recovered from https://www.britannica.com/biography/Erwin-Schrodinger
Khan Academy. (2023). The quantum mechanical model of the atom. Recovered from https://www.khanacademy.org/science/physics/quantum-physics/quantum-numbers-and-orbitals/a/the-quantum-mechanical-model-of-the-atom#:~:text=Summary&text=mvh-,Erwin%20Schr%C3%B6dinger%20proposed%20the%20quantum%20mechanical%20model%20of%20the%20atom,treats%20electrons%20as%20matter%20waves.
Howgego, J. (s/f). Schrödinger’s cat. NewScientist. Recovered from https://www.newscientist.com/definition/schrodingers-cat/]]> 2023-03-30 19:03:50 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538855047 giaballon2008 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538856576 Libretext Chemistry. (2023). Postulates of Dalton's Atomic Theory. Recovered from https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Atomic_Theory/Dalton's_Atomic_Theory/Postulates_of_Dalton's_Atomic_Theory]]> 2023-03-30 19:05:00 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538856576 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538882509 He was a French Scientist that in 1924 state that the particles could be described also as waves. He discover this by observing the way streams of electrons were reflected against crystals and spread through thin metal foils. This gave him a Nobel price in 1929. ]]> 2023-03-30 19:30:50 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538882509 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538886480 He also propose in 1924 that electrons and other types of matter that were consider only as material particles also have wave properties. This was a very important contribution to the wave-particle duality. 
Sources 
 Lovvet Cline, B. (2023). Louis de Broglie. Britannica. Recovered from https://www.britannica.com/biography/Louis-de-Broglie
Editor of Britannica. (2023). wave-particle duality. Britannica. Recovered from https://www.britannica.com/science/frequency-physics]]> 2023-03-30 19:35:06 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538886480 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538893278 In 1897 he discovered the electron and he concluded that atoms were a sphere of psoitive charge with electrons (-e) incrusted in it. ]]> 2023-03-30 19:42:57 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2538893278 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539082583 He was british Scientist that observed and measured the X-ray spectra of various chemical elements using diffraction in crystals. Discovering the relation between wavelength and atomic number know as Moseley’s Law. With that theory he discover the number of lanthanides and showed the gaps in the atomic number sequence at numbers 43, 61, 72, and 75. ]]> 2023-03-31 00:15:27 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539082583 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539085414  With this discover he rearranged the elements in the periodic table in order of atomic numbers and it was found that this resolved the disparities in earlier forms of the periodic table that were based on atomic masses.
Source
Dizdaroglu, M. Hart, M. (2012). Henry G. J. Moseley. Recovered from https://www.microscopy.org/images/posters/Moseley.pdf
Editors of Britannica. (2022). Henry Moseley. Recovered from https://www.britannica.com/biography/Henry-Moseley]]> 2023-03-31 00:18:28 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539085414 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539101687 He create the atomic Hydrogen model in 1913. Whit this he create an atomic model whit positively charged nucleus, comprised of protons and neutrons, surrounded by a negatively charged electron cloud that orbit in shells. ]]> 2023-03-31 00:32:26 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539101687 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539122338 To discover he experimented with cathode ray tube. He created an experiment called The Cathode ray experiment. In this experiment Thomspon created a glass tube that had all the air drained out of it. Then he applied high electric voltage at one end of the tube between two electrodes. He observed a ray coming out of the cathode (negative charged) to the Anode (positive charged). ]]> 2023-03-31 00:49:34 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539122338 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539125834 Source 
Faust, M. (2023). Bohr's Hydrogen Atom. Recovered from https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Quantum_Mechanics/09._The_Hydrogen_Atom/Bohr's_Hydrogen_Atom#:~:text=Niels%20Bohr%20introduced%20the%20atomic,the%20nucleus%20in%20atomic%20shells.
The editors of Britannica. (2022). Bohr model. Britannica. Recovered from https://www.britannica.com/science/Bohr-model]]> 2023-03-31 00:52:39 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539125834 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539134255 The plum pudding Model is Thompson's Atomic Model. It is a cloud of positive charge and electrons. It's called like that because it the electrons look like the dried fruit in a christmas pudding.
Sources:
BYJU'S. (2021). What is Cathode Ray Tube?. Recovered from https://byjus.com/chemistry/cathode-ray-experiment/#:~:text=The%20Cathode%20ray%20experiment%20was,in%20the%20history%20of%20physics.
ABCTE. (2007). Modern Atomic Theory: Models. Recovered from http://www.abcte.org/files/previews/chemistry/s1_p5.html#:~:text=In%201897%2C%20J.J.,charged%20particles%20in%20neon%20gas.

]]> 2023-03-31 00:59:01 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539134255 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539144384 In 1891 Rutherford described the atom as having a tiny, dense, and positively charged core called the nucleus, he also said that the mass of the atom was on the nucleus. He also stated that electrons circulated around the nucleus llike the earth revolves around the sun. ]]> 2023-03-31 01:06:50 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539144384 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539184635 The experiment consists of a piece of gold phoil being hit by alpha particles. Alpha particles are nucleus, of 2 protons and 2 neutrons, that don't have their electrons around it. A few of the particles were deflected by the foil. He concluded that a tiny dense nucleus in the atom was causing the deflections. ]]> 2023-03-31 01:37:18 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539184635 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539192299 The Rutherford Atomic model is also known as the Rutherford Planetary Model.
Sources:
Britannica. (2023). Rutherford model. Recovered from https://www.britannica.com/science/Rutherford-model
Primary Connections. (n/d). Rutherford atomic model. Recovered from https://www.primaryconnections.org.au/themes/custom/connections/assets/SBR/data/Chem/sub/atom2/atom2.htm#:~:text=In%201911%2C%20Rutherford%20described%20the,planets%20revolving%20around%20the%20Sun.
Britannica Kids. (2023). Rutherford, Ernest: Gold foil experiment. Recovered from https://kids.britannica.com/students/assembly/view/124956#:~:text=Physicist%20Ernest%20Rutherford%20established%20the,nucleus%20was%20causing%20the%20deflections. ]]> 2023-03-31 01:43:48 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539192299 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539204078 Max Planck was a German theoretical physicist who   deduced the relationship between the energy and the frequency of radiation 1900. His contribution to the atomic theory was that different atoms and molecules can emit or absorb energy in discrete quantities (can only take on certain values) only. The smallest amount of energy can be emitted or absorbed in the form of electromagnetic radiation which is called quantum. ]]> 2023-03-31 01:54:17 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539204078 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539205944 2023-03-31 01:55:50 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539205944 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539928811 Sources:
BYJU'S. (2019). Planck's Quantum Theory: Quantization Of Energy. Recovered from https://byjus.com/chemistry/planks-quantum-theory/#:~:text=According%20to%20Planck's%20quantum%20theory,radiation%20is%20known%20as%20quantum.
Britannica. (n/d). Max Planck. Recovered from https://www.britannica.com/biography/Max-Planck]]> 2023-03-31 14:03:08 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2539928811 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540223391 2023-03-31 18:44:46 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540223391 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540225452 2023-03-31 18:47:11 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540225452 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540227271 2023-03-31 18:49:35 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540227271 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540228482 2023-03-31 18:50:29 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540228482 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540230807 2023-03-31 18:53:21 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540230807 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540231516 2023-03-31 18:54:10 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540231516 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540233330 James Chadwick was an English physicist who received the novel prize for physics in 1935 for the discovery of the neutron, he also discover the proton with Rutherford. He performed many experiments stating that the radiation his German colleagues talked about contained uncharged particles of about the mass of a proton. The particles were called neutrons and his theory spread quickly, earning a great reputation amongst other scientists all over the world. Energy is transferred only in certain well-defined quantities. They have neither a positive nor negative charge.
Britannica. (2020). James Chadwick british physicist, Britannica. Recovered from James Chadwick | Biography, Model, Discovery, Experiment, Neutron, & Facts | Britannica


]]> 2023-03-31 18:55:49 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540233330 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540233510 2023-03-31 18:56:06 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540233510 giaballon2008 https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540234561 Libretex Chemistry. (2023). Proust's Law of Constant. Recovered of: Proportionhttps://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Atomic_Theory/Dalton's_Atomic_Theory/Proust's_Law_of_Constant_Proportion#:~:text=The%20French%20chemist%20Joseph%20Proust,the%20same%20proportion%20by%20mass.%22]]> 2023-03-31 18:57:15 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540234561 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540236482 2023-03-31 18:59:49 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540236482 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540237024 2023-03-31 19:00:32 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540237024 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540237609 2023-03-31 19:01:02 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540237609 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540239041 2023-03-31 19:02:21 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540239041 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540260114 Group 4: Macarena de la Piedra, Gia Ballon, Bastian Burga and Adriano Camino]]> 2023-03-31 19:30:31 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540260114 amdlpied https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540260863 Macarena de la Piedra, Gia Ballon, Bastian Burga and Adriano Camino]]> 2023-03-31 19:31:42 UTC https://padlet.com/amdlpied/tjnopzrc7pq65dol/wish/2540260863