The periodic table is an identifiable scientific resource that is used to display the elements that make up all matter. Elements are the simplest matter and cannot be broken down into purer substances using chemical methods . The periodic table shows all elements and there are over 100. The discovery of the periodic table was a pinnacle in science as it categorizes the elements by their various chemical and physical properties.
Even in ancient times, people had always been aware of elements like gold, silver and copper. In 350 BCE, Aristotle had a theory that all matter was made up of the elements of earth, fire, air and water . He believed that lighter objects had less earth than heaver objects. He even spoke of a 5th substance, aether, a weightless and incorruptible substance that makes up the sun, moon, planet and stars .
Much Later, in 1649, Hennig Brand discovered the first element, phosphorus, as he tried to make a philosopher’s stone while experimenting with distilled human urine. This got people thinking about which substances are elements. In 1661, Boyle defined an element as "a substance that cannot be broken down into a simpler substance by a chemical reaction". This definition was used until subatomic particles were discovered .
In the 1700’s, Antoine Lavoiser wrote the first extensive list of elements and categorized them into metals and non-metals . Johann Wolfgang Döbereiner and Alexandre-Emile Béguyer de Chancourtois also tried to classify the elements in the mid 1800’s but were not extremely successful. Döbereiner classified elements into triads with elements with similar properties while Béguyer de Chancourtoiswas the first to notice that when elements are arranged by their atomic weights, groups of elements ...
... middle of paper ...
...he same regardless of the type of atom. He then concluded that atoms consist of tiny, negatively charged particles. He, like Chadwick, received a Nobel prize for his work in 1906 .
John Dalton was another English scientist to make significant contributions to science. Dalton was born in 1766 and spent a lot of his life studying the air and gases. This led him to make discover that chemical combinations consist of the interaction of atoms. He published his thoughts on atoms in 1805 . Dalton’s atomic theory states that all matter is made of atoms, atoms are indivisible and indestructible, all atoms of a given element are identical is mass and properties, compounds are formed by a combination of two or more different kinds of atoms and that a chemical reaction is a rearrangement of atoms . This atomic theory is known as a foundation for many discoveries in chemistry.
Attempts to organize the elements began in the late 1800’s. At this time, about sixty elements were known. Much advancement would have been impossible if the basic model of the atom was discovered. Great progress came from Dmitri Medeleev – a Russian chemist. His first draft of a periodic table was only the product of him attempting to summarize his knowledge of the elements. Although not all of Medeleev’s ideas were one-hundred percent accurate, they created a solid base to build upon. Marie and Pierre Curie; a married couple from Paris were successors of Medeleev. Their interests were radioactivity and discovered radium. The true pioneers of the periodic table were Ernest Rutherford and James Chadwick. Rutherford formed the hypothesis that, “An atom must have a concentrated positive center charge that contains most of the atom’s mass.” Following Rutherford, Chadwick exposed a segment of the nucleus that was had no charge: the neutron. With the basic knowledge of the structure of an atom, the tedious work of putting the rest of the puzzle together continued.
Dalton’s atomic theory, which stated “the atoms were tiny, indivisible, indestructible particles” (Bender), differed drastically from that of the Greeks’ in that it “wasn’t just a philosophical statement that there are atoms because there must be atoms” (Bender). Although Aristotle believed that there are four terrestrial elements, earth, water, air, and fire, Democratus believed that “a piece of a substance can be divided into smaller pieces of that substance until we get down to a fundamental level at which you can’t divide the substance up and still have pieces of that substance” (“Atoms”). Aristotle’s theory was popular, but incorrect; Democratus’s was closer to our current theory, yet he remained relatively unpopular and obscure. This demonstrates of the key way in which a personal point of view can, in fact, retard the pursuit of knowledge. The scientist with the better oratory abilities has his theories more widely accepted. Dalton’s own theory, which extrapolated upon four basic
These Greek philosophers came up with the idea that all matter is composed of indivisible elements.
Many scientists helped with this. In 465 B.C. Democritus named the atom “can’t be divided” (OI). He proposed that matter was made of atoms (Doc. 1). Later, Lavoisier introduced the Law of Conservation of Matter. It stated that matter couldn’t be created or destroyed. After that, John Dalton published the Atomic Theory of Matter in 1803 (Doc. 2). It said that matter is made of atoms that are too small to be seen by the naked eye, and that each type of matter is made of only one kind of atom (OI). J. J. Thomson observed electrons using cathode rays. A few years later, Ernest Rutherford bombarded an extremely thin piece of gold foil with positively charged alpha particles. Most of the protons passed through the foil, but some bounced off. Rutherford concluded that the atom must be composed of mostly empty space. He also realized that the alpha particles must have bounced off something else that had positive charge. The positively charged objects were protons. Neutrons were discovered by James Chadwick. To conclude, the theories of the atom have been modified a lot since the
In 1801 he argued that the atmosphere was filled with mechanical gases and that the chemical reactions between the nitrogen and oxygen played no part in the atmosphere?s construction. To prove this he conducted a lot of experiments on the solubility of gases in water. This showed that dissolved gases were mechanically mixed with the water and weren?t mixed naturally. But in 1803 it was found that this depended on the weight of the individual particles of the gas or atoms. By assuming the particles were the same size Dalton was able to develop the idea of atomic weights.
Until the nineteenth century the model of the atom resembled a ball, it was thought to look like a small sphere. But in 1897, J. J. Thomson changed the view of the atom with his discovery of the electron. Thomson's work suggested that the atom was not an indivisible particle, like John Dalton said it is like a jigsaw puzzle made of smaller pieces.
Every since the beginning of history, scientist have been making many advancements. Science can be so complex and is constantly being readjusted due to learning new knowledge. Scientists, John Dalton, J.J. Thomson, and Niels Bohr, are just a few who have contributed to our modern understanding of an atom.
When and how the element was discovered including who discovered it and the circumstances and/or investigations that lead to them discovering the element?
The next big step in the discovery of the atom was the scientific test that proved the existence of the atom. After the discovery of the atom we had the discovery of subatomic particles. With the discovery of the subatomic particles came the research, which came from experiments that were made to find out more about the subatomic particles. This research is how we uncovered that most of the weight of an atom is from its nucleus. With the gold foil experiment, tested by Ernest Rutherford, he discovered the existence of the positively charged nucleus. He proved this when the experiment was happening, a small fraction of the photons th...
The Atomic Theory began in roughly 400BC with Democritus in Ancient Greece and is universally believed to be correct today. Democritus who was born in 460 BC and died 370 BC and is known as the father of modern science. Democritus proclaimed that everything is made up of atoms. He continued his theory to say that atoms will always be in motion, between atoms there is empty space, atoms are unbreakable, there are an infinite number of atoms all different sizes and shapes. He also said that iron atoms are solid and strong and have hooks to lock them together, water atoms are smooth and slippery, salt atoms have sharp jagged edges because of its taste and air atoms are light and spiralling.
The Periodic Table of Elements is commonly used today when studying elements. This table’s history begins in ancient times when Greek scientists first started discovering different elements. Over the years, many different forms of the periodic table have been made which set the basis for the modern table we use today. This table includes over 100 elements and are arranged by groups and periods. Groups being vertical columns and periods being horizontal columns. With all of the research conducted over the years and the organization of this table, it is easy to use when needed.
Things are very different from each other, and can be broken down into small groups inside itself, which was then noticed early by people, and Greek thinkers, about 400BC. Which just happened to use words like "element', and `atom' to describe the many different parts and even the smallest parts of matter. These ideas were around for over 2000 years while ideas such as `Elements' of Earth, Fire, Air, and Water to explain `world stuff' came and went. Much later, Boyle, an experimenter like Galileo and Bacon, was influenced much by Democritus, Gassendi, and Descartes, which lent much important weight to the atomic theory of matter in the 1600s. Although it was Lavoisier who had divided the very few elements known in the 1700's into four different classes, and then John Dalton made atoms even more believable, telling everyone that the mass of an atom was it's most important property. Then in the early 1800's Dobereiner noted that the similar elements often had relative atomic masses, and DeChancourtois made a cylindrical table of elements to display the periodic reoccurrence of properties. Cannizaro then determined atomic weights for the 60 or so elements known in the 1860s, and then a table was arranged by Newlands, with the many elements given a serial number in order of their atomic weights, of course beginning with Hydrogen. That made it clear that "the eighth element, starting from a given one, is a kind of a repeat of the first", which Newlands called the Law of Octaves.
Dalton was the first person to develop a scientific atom theory, the ancient Greeks had ideas about the atom but could not prove it scientifically.
Believed to be the first atomic theorist, the Greek materialist philosopher Democritus explored the nature of stones in 400 B.C. Democritus split a stone in half and concluded that the two halves have the same properties; the only difference between them and the original was size. However, that observation did not hold forever because the more he split the stone pieces into halves, the tougher the process was. At one point, he tried his best but failed to split a small stone piece. He called it "atomos," which is the Greek word for indivisible. The first major observation to atomic theory was thus made: matter is composed of sub-parts which are unvarying and indivisible. He also hypothesized two ideas: different atoms were only different in aspects regarding shape and size, and all atoms are always in motion, resulting in some collisions which cause dissociations or combinations (changes in state of matter).
Scientists from earlier times helped influence the discoveries that lead to the development of atomic energy. In the late 1800’s, Dalton created the Atomic Theory which explains atoms, elements and compounds (Henderson 1). This was important to the study of and understanding of atoms to future scientists. The Atomic Theory was a list of scientific laws regarding atoms and their potential abilities. Roentagen, used Dalton’s findings and discovered x-rays which could pass through solid objects (Henderson 1). Although he did not discover radiation from the x-rays, he did help lay the foundations for electromagnetic waves. Shortly after Roentagen’s findings, J.J. Thompson discovered the electron which was responsible for defining the atom’s characteristics (Henderson 2). The electron helped scientists uncover why an atom responds to reactions the way it does and how it received its “personality”. Dalton’s, Roentagen’s and Thompson’s findings helped guide other scientists to discovering the uses of atomic energy and reactions. Such applications were discovered in the early 1900’s by using Einstein’s equation, which stated that if a chain reaction occurred, cheap, reliable energy could b...