1800-1875+(Mark+Holmes)


 * 1800-1875 FINAL **


 * John Dalton (1766-1844)**

[] ...**The Atom Song!!**

[] ...**Dalton Video**

John Dalton was a scientist who was born in Cumberland, England in 1766. Dalton grew up in a time period where there wasn't a lot of discoveries or imformation about the atom. The world had just gotten over the Dark Ages where Plague and Relgion lead to the deaths of many scienists and such. However, Dalton was an extremely gifted scientist, and through hard work and determination he better helped the world understand the atom. Dalton helped do so through Dalton's Atomic Theory, which was built off of Democritus's initial atomic theory thousands of years before. Through his experiments, Dalton was able to create a rough draft per say, of the periodic table as shown in the picture above. With the lack of technology, Dalton was still able to discover many elements like hydrogen, oxygen, iron, gold, copper, zinc, and mercury. Some of the data he collected for his able was incorrect, but he helped start up the Periodic Table known worldwide today. By organizing this table and through his atomic theory, Dalton was one of the most significant scientists relating to the discovery of the atom to ever live (if not the most important).

John Dalton's Theory was composed of five main points listed here: With these main points, the understanding of the atom increased significantly for scientists and people worlwide. These points helped Dalton come up some of the elements we know today in the first periodic table. He was able to organize many elements including the first element Hydrogen in the periodic table. Dalton's discovery bettter helped the world understand the atom and also what atoms put together make, elements. Before Dalton, the atom was simply known as an indistructable and invisible. However, after Dalton, the world now knew that atoms make up elements, and that those elements can therefore make up compound. John Dalton is a pioneer of the basic understanding of atoms and how they are viewed today.
 * Elements are made of tiny particles called atoms.
 * All atoms of a given element are identical.
 * The atoms of a given element are different from those of any other element; the atoms of different elements can be distinguished from one another by their respective relative weights.
 * Atoms of one element can combine with atoms of other elements to form chemical compound; a given compound always has the same relative numbers of types of atoms.
 * Atoms cannot be created, divided into smaller particles, nor destroyed in the chemical process; a chemical reaction simply changes the way atoms are grouped together.

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 * Demitri Mendeleev (1834-1907)**

Dmitri Mendeleev was both a chemist and inventor who was born in Tobolsk, Russia during the year 1834. Growing up, Dmitri was from an extremely poor family, yet he still managed to become a successful scientist and create one of the most important inventions used for chemistry today, the Periodic Table. Dmitri created the Periodic Table in the year 1871, and built a lot of his works off of John Dalton's Atomic Theory and his "rough draft", of the table and also the work of John Newlands and Lothar Meyer and their discovery of different elements. During Mendeleev's lifetime, Russia was in poor condition and not exactly the best place to work, even for a scientist. However, through pure intellgience, hard work, and hints from previous scientists before him, Mendeleev made history through the discovery of the Period Table, which is used in classrooms and work places all over the world.

As you already know, Mendeleev's discovery was the creation the Period Table. Now, Mendeleev was an intelligant man and noticed that the atomic weight of atoms could be used to rank different elements from lightest to heaviest. Furthermore, he would constantly stress the fact that there was an order to elements, and that putting the elements in order would help predict undiscovered elements (and he was correct!). Although Mendeleev's Period Table had a few errors, his organization of elements through atomic weight helped further overall understanding of the atom and its organization and also helped scientists throughout the world the ability to discover new elements and add them to the table. Below is a picture of Mendeleev's 1869 Period Table;

//Mendeleev's elements (1869) compared to periodic "Groups."

And Today's Table!!!!!!

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As you can notice, compared to todays Period Table (shown below Mendeleev's Table), Mendeleev was extremely accurate with his discoveries of elements as well as the order of the elements.

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 * G.J. Stoney (1826-1911)**

-Electron in motion around nucleus

G.J. Stoney was an Irish Physist born in the year 1826 in the Irish Midlands. Stoney grew up during the Great Famine, where many Irish folks left the country due to starvation because of poor farming conditions. At a young age his family lost their land due to the Great Famine, yet Stoney was still abel to attend a prestigious college in Ireland and become a famous physisist throughout the world. G.J. Stoney is known for many different reasons, but he is best known for his orgional discovery of the electron in the year 1874. Stoney's most important scientific work was the conception and calculation of the magnitude of the atom or particle of electricity, for which he coined the term "electron" ([]). The fact that Stoney was able to discover the electron at such an early point in time is truly amazing.

Stoney's discovery of the electron helped understand the atom in many different ways. Before this discovery, the atom was thought of as just an atom, the smallest indistinguishible unit of an element. However, after this discovery, the world discovered that the atom is not the smallest unit in the world, and that there are subsystems that make up the atom. Therefore, the discovery of the electron (which is a part of the atom that orbits outside of the nuclues) better helped the world understand the atom and helped scienists discover that the atom alone, isn't the smallest unit the the world.

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