The Development Of The Periodic Table

The students created a macroscopic, three-dimensional (3D) model of several properties of the periodic table. They explained in their own words the following terms: atomic radii, ionic radii, first ionization energy, and electronegativity. Lastly, they identified, described, and explained the patterns observed in the 3D periodic tables for the following element properties: atomic radii, ionic radii, first ionization energy, and electronegativity.

Explain how scientific observations led to the development of, and changes to, the periodic table.

He stated that this was a mysterious force but never continued his research on it. Then in 460 B.C. there was a philosopher named Democritus. Democritus and his mentor Leocippus posed the question that if he broke bread into multiple pieces how many would breaks would it take until there was no more bread. He then was able to make a few theories being all matter was created of atoms and atoms are solid but not invisible. However, there was a man named Aristotle and many other philosophers who disagreed with Democritus and said matter was composed of four main elements. Earth, fire, air, and water. For example, a liquid was made of water and a stone was made of rock. Therefore, Democritus’s theory “ was rejected by Aristotle, one of the most influential philosophers of Ancient Greece; and the atomic theory was ignored for nearly 2,000 years.”(

The book “The Periodic Table” by Primo Levi is undoubtedly a masterpiece. It showcases the enthusiasm, the level of dedication, and passion successful chemists such as Primo Levi himself had for the field of their expertise. The way Primo Levi has related the troublesome times and events he had to face in prospect with the elements of the periodic table is laudable. Primo Levi is surely an inspiration and a perfect example of prodigy and passion. Despite the challenges and the hardships inflicted on him by the bigoted group of Germens, he still managed to emerge as an exceptional chemist and an author who made great contributions to the modern chemistry as we now know it.

The periodic table is a table that categorises and displays all of the chemical elements. It is made up of groups, periods and blocks. A group (also referred to as a family) are the columns of elements, there are 8 groups. The elements in each family have similar but not identical properties and they all have the same number of outer electrons. E.g. lithium (Li), sodium (Na), potassium (K) are all soft, white, shiny metals because they are all members of group 1. A period is each horizontal row of elements, there are 7 periods. In a period, the elements are not alike in properties, the first element in a period is always an extremely active solid, and the last element in a period is always an inactive gas. Properties change greatly across a given row. Each new period represents the next shell which electrons fill. A block is a region of the periodic, there are 4 blocks: S, D, P and F.

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.

Bohr is well known for his amazing research on the structure of the atom, he thought that maybe the hydrogen atom was based on the quantum theory that energy can only be transferred in one way, and he also thought that E. rutherford model had some problems, so he fixed

Each different scientist made an impact in some way to the origins of an atom. Lucretius’s work, De Rerum Natura, was the basis for many future scientists. Robert Boyle was a very religious man and people believed that was the reason for him not marrying. Boyle constructed the idea that the air was made up of different particles with each having different functions. Huygens first thought of the idea that waves of light moved in a spherical shape. His wave theory is still used today along with Maxwell’s electromagnetic theory. Isaac Newton is highly popular for his theory of gravity. Bernoulli began with the idea of the kinetic theory of gases in his work, Hydrodynamics. Newton gave the image to a lot of scientists after him of what an

Periodic Table and Periodic Law Experiment Date: March 16, 2017 20170004 강동현 Co-worker: 박정언 Introduction In 1869, Dmitri Mendeleev and Lother Meyer separately made the periodic table, which showed that the properties of chemicals recur periodically. However, both periodic tables sorted the elements in order of increasing atomic mass.

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.

The atomic model that was accepted by the scientific community before Rutherford's experiment consisted of a group of positive charge surrounded by electrons to balance the negative charge of the electrons. In Rutherford's experiment, he found that there was a center to atoms, later to be named the nucleus. Rutherford created his own model after stating that Thompson's was incorrect.

Throughout history the periodic table of elements has been influenced and amended by multiple scientists. These scientists include Johann Dobereiner, A.E Beguyer de Chancourtois, John Newlands, and Glenn Seaborg. As well as Dmitri Ivanovich Mendeleev and Lothar Meyer the creators of the periodic table. There are many ways that the periodic table of elements was set out. For example the table can be organized using patterns between atomic numbers, electronegativity, ionization energy, structure (gas or solid) valence electrons and electron configuration (shells) as seen in the modern day periodic table.

Before Rutherford’s Geiger-Marsden experiment the most popular model of the atom was the “plum pudding model” developed in 1904 by the person who also discovered the electron in 1897, J.J. Thompson. It was the most common model of the atom and stated that electrons (plum) floated around with

Atomic Theories 1. John Dalton John Dalton based his theory on Democritus’ findings. This was that matter could be divided and split into several smaller “units”, eventually forming a tiny particle that couldn’t be divided. This particle is an atom. Democritus and other Ancient Greeks could not support their theory or findings due to the lack of technology, equipment and understanding of atoms.

As technology advances so do the experiments to discover more about the atom. By 1911, Rutherford disproved Thomson's plum pudding model with his gold foil experiments. He discovered that atoms are mostly empty space and deflections are caused between a repulsive force between the positively charged nucleus and the alpha particles. James Chadwick, a co worker of Rutherford, found that there was another subatomic particle located in the nucleus called the neutron. While Rutherford’s model of the atom showed the electrons orbiting the nucleus, Bohr’s model shows the electrons traveling around the nucleus, the distance of the electrons from the nucleus are determined by energy. Then in the late 1910’s, Robert Millikin calculated the mass of a single electron by performing the oil droplet