The Periodic Table
The periodic table of elements is a chart or table that organizes all the known elements ever found. It is a useful chemistry tool for chemists and students. Each element has its own atomic number. There are 118 elements that are on the periodic table. Each element has a colour and the colours make the categories. I have listed the elements by the categories. There are eleven categories: alkali metals, alkaline earth metals, actinides, lanthanides, transition metals, post transition metals, metalloids, other non-metals, halogens, noble gases, and unknown chemical properties. Alkali metals is red, alkaline earth metals is yellow, actinides is pink, lanthanides is purple, transition metals is peach, post transition metals is gray, metalloids is beige, other non-metals is green, halogens is highlighter yellow, noble gases is blue, and unknown chemical properties is white. Its also sorted by their atomic mass.
Invention
Dmitri Mendeleev is the Russian chemist who helped make the periodic table in 1869. Dmitri Mendeleev first invented the beginning of the periodic table when there was 60 elements discovered. Dmitri didn’t make the periodic table you see today. He started the idea of organizing all the elements and left space for more elements to be discovered. There have been 58 more elements that have been discovered and added to the periodic table since the beginning. He was born on February 8th, 1834 and passed away on February 2nd, 1907.
History and Discovery
Timeline
In 1669, German merchant and amateur alchemist Hennig Brand attempted to create a Philosopher’s Stone; an object that supposedly could turn metals into pure gold. He heated residues from boiled urine, and a liquid dropped out and burst into flames. This was the first discovery of phosphorus.
In 1680, Robert Boyle also discovered phosphorus and it became public.
In 1809 at least 47 elements were discovered and scientists began to see patterns in the characteristics.
In 1863, English chemist John Newlands divided the then discovered 56 elements into 11 groups, based on characteristics.
In 1869, Russian chemist Dmitri Mendeleev started the development of the periodic table, arranging chemical elements by their atomic mass. He predicted the discovery of other elements, and left spaces open in his periodic table for them.
In 1886, French physicist Antoine bequerel first discovered radioactivity. Thomson student from New Zealand, Ernest Rutherford named three types of radiation; alpha, beta, and gamma rays. Marie and Pierre Curie started working on the radiation of uranium and thorium, and subsequently discovered radium and polonium. They discovered the beta particles were negatively charged.
In 1894, Sir William Ramsay and Lord Rayleigh discovered noble gases, which were added to the periodic table as group 0.
In 1897, English physicist J. J. Thomson first discovered electrons; small and negatively charged particles in an atom. John Townsend and Robert Millikan determined their exact charge and mass.
In 1900, Bequerel discovered electrons and beta particles as identified by the Curies are the same thing.
In 1903, Rutherford announced that radioactivity is caused by the breakdown of atoms.
In 1911, Rutherford and German physicist Hans Geiger discovered that electrons orbit the nucleus of an atom.
In 1913, Bohr discovered that electrons move around a nucleus in discrete energy called orbitals. Radiation is emitted during movement from one orbital to another.
In 1914, Rutherford first identified protons in the atomic nucleus. He also transmitted a nitrogen atom into an oxygen atom for the first time. English physicist Henry Moseley provided atomic numbers, based on the number of electrons in an atom, rather than based on an atomic mass.
In 1932, James Chadwick first discovered neutrons, and isotopes were identified. This was the complete basis for the periodic table. In that same year, Englishman Cockroft and the Irishman Walton first spilt an atom by bombarding lithium in a particle accelerator, changing it to two helium nuclei.
In 1945, Glenn Seaborg identified lanthanides and actinides (atomic number 92) which are usually placed below the periodic table.
Elements That We Use Everyday
Without realizing it, people use elements from the periodic table everyday. We use pennies, tin foil, pencil lead, gold rings and bracelets, and silver necklaces. Most people don’t think about it when they get a silver bracelet or use a penny. They don’t realize they’re using an element from the periodic table of elements.
Conclusion
Finally, I’ve learned about the periodic table of elements on this report. I have learned how it sorts the elements in a table, with their symbol, atomic number, and their full name. I learned that the periodic table of elements is actually sorted by each element’s atomic mass and it’s sorted into different colours and categories because of the similarities in characteristics. Lots of people use it today like, chemists and even high school students. Dmitri Mendeleev had a brilliant idea to create the periodic table of elements.
Bibliography
Books:
The Big Book of Knowledge
Internet:
www.aip.org
www.webelements.com
www.lenntech.com
www.chemicool.com
Cara's Blog 