The Periodic Table Of Elements

For the lesson observed the objectives was to explain the trends of the periodic table based on the elements’ valence electrons and atomic numbers. Additionally, students were responsible for applying their previous knowledge in calculating subatomic particles to review the Bohr Models and discus the relationship among families in the periodic table. Students will use the information from today’s lesson to make future judgments on reactivity and bonding created during chemical reactions in the next unit. Lastly, students were to connect the information on elemental properties to previous experiences with their health, commercial products, and everyday life.

John Dalton wrote the modern atomic theory, a fundamental component of that is, the mole ratios of elements in a compound will be small whole numbers.

The history of the atomic theory is thoroughly extensive. It had all started around 400 BCE when few people believed in an atomic theory, that atoms are building blocks. Democratic believed matter was made up of tiny particles. He called them atomos. Democratic is Leucippus’ most infamous pupil Later in history, the law of definite proportions was discovered. Two samples of given compounds are made of the same elements in exactly same proportions by mass regardless of the size or sources of the samples. After this came the law of conservation of mass and law of multiple proportions. Around 1808, John Dalton came up with a different atomic theory. He used Greek concept of the atom and all of the laws previously mentioned to acquire his

-Henry Gwyn Jeffreys Moseley- Worked with Ernest Rutherford, experimented with 38 metals, he found that the positive charge of each element’s nucleus increased by one from element to element as they were arranged in Mendeleev’s periodic table, lead to modern definition of atomic number (# of protons in atom’s nucleus) and the recognition the

In 1787, an unusual rock had come across the work of Dr. Adair Crawford when investigating witherite, a mineral in Strontian, Scotland ("Strontium | Periodic Table." Royal Society of Chemistry). The discoverer of the element was testing the results of witherite and hydrochloric acid. When Dr. Crawford mixed witherite with hydrochloric acid he did not get the results he expected. He assumed that his sample of witherite was contaminated with an unknown mineral, a mineral he named strontianite ("The Element Strontium." It's Elemental). The discovery by Dr. Adair Crawford was the start of strontianite, but it was not the end of research on this element. Although Dr. Crawford technically discovered strontianite, he did not prove that it was a new element. In 1791, Thomas Charles Hope, continued the investigation of strontianite ("Strontium | Periodic Table." Royal Society of Chemistry). Through his investigation, Hope proved that strontianite was a new element. Finally the element, now known as Strontium, was isolated. Strontium was first isolated by Sir Humphry Davy, an English chemist, in 1808 through the electrolysis of a mixture of strontium chloride and mercuric oxide ("The Element Strontium." It's

Chapter 12 of Kean’s bestseller focuses on how politics had a major influence on the development of the periodic table. The majority of the chapter takes place during the mid-1900s and therefore, as one might

The second main contributor toward the atomic structure was John Dalton. John Dalton was the one who brought the atomic theory talk back into play after 2000 years from Democritus. Dalton become fond of the atomic structure following his love from meteorology. He claimed that the forces of repulsion that caused pressure only were between the same atoms and the atoms inside a mixture had different weights and complexity. He then decided to calculate the atomic weights by determining the percentages of each composition in a compound. This allowed him to be able to

Over the course of the last 5000 years, mankind’s knowledge has been constantly advancing. Chemistry, a branch of science, has experienced a tremendous leap and expansions since ancient Greek civilization. One of the major breakthroughs in the advancement in Chemistry was the creation of the Atomic theory, which laid a foundation for the modern-day Chemistry and future of science. The Atomic theory introduced the idea of atoms, which are defined as the discrete units of matter. There are five key scientists that significantly contributed to the Atomic model over a span of thousands of years. They are: Democritus, John Dalton, J.J. Thompson, Ernest Rutherford, and Niels Bohr.

Stanislao Cannizzaro was born on July 13, 1826. When he was younger, he showed great skills in mathematics. He later became an assistant to Rafaelle Piria. Cannizzaro saw his dedication to his work that Piria influenced him to transform his study to chemistry. Cannizzaro later determined the different atomic weights. Dmitri Ivanovich Mendeleev always had a love for history, math, and physics. He attended the University of St. Petersburg where he formed the ideas of chemical compounds. Mendeleev found out that you could simplify the periodic table by separating them into different groups. He arranged them by the atomic weights and then later realized they had similar chemical properties. He had also given predictions of future elements and their properties.

By the year 1869, a collection of 63 elements had been revealed. As the number of known elements increased, scientists began to notice patterns in properties and formulate classification schemes. In 1862, a French geologist, A.E.Beguyer de Chancourtois, recorded a list of the elements on a cylinder regarding their individual atomic weights. He was the first to identify that elemental properties reoccur every seven elements.

Who was Demetri Mendeleev and what is his contribution? 14. What is the periodic table? 15. What are groups/families?

It was discovered by a man known as Friedrich Stromeyer from Göttingen University. He discovered it while trying to solve the problem which was brought up when apothecaries of Hanover, Germany, made zinc oxide. The zinc oxide was discolored instead of being pure white. Stromeyer traced the discoloration to a component which was not known to the world. He produced a blue-grey metal which he called Cadmium after the mineral. Cadmium comes from the latin word cadmia, meaning calamine. Calamine is zinc oxide which Cadmium originated from.

Can you believe that in 1869 Russian Chemist Dimitri Mendeleev arranged the chemical elements by atomic mass and started the development of the periodic table. After this Henry Gwyn Moseley was an English Physicist and Developed Mosley's which sorted the chemical elements of the periodic table in a logical order based on physics. Before all the naturally occurring elements were discovered the periodic table was used to predict chemical and physical properties of elements in the gaps of the table. The periodic table can now be used to predict properties of elements yet to be discovered. It can also be used to predict types of chemical reactions. The Periodic

Without Julius Meyer, there would be no periodic table as there is today. He was the human who realized that the properties of an element a part of the periodic table all depended on the atomic weight, (Chem Heritage). He had some of the very first ideas that led to the first copies of our periodic table in the 1870’s (Chem Heritage). Julius Lothar Meyer had figured out and organized 28 of the elements back in the 1800’s into six families. He did this by figuring out the physical and chemical characteristics that were similar to each other in each element. He organized them depending on the valence of each element. Valence is the number that represents combining power of an atom of a particular element. Meyer saw that there were some elements missing as he organized them according to the atomic weight, and left some spots

1869 - Mendeleev produced a periodic table based on atomic weights but arranged 'periodically '. Elements with similar properties appeared under each other.