Exploring the Role of Chemists
It was Lavoisier who divided the few elements known in the 1700's into
four classes, and then John Dalton made atoms even more convincing,
suggesting that the mass of an atom was it's most important property.
In the nineteenth century Johann Döbereiner was the first to attempt
to classify elements using their relative atomic mass. He also
identified a number of ‘triads’ in the list of elements then known.
Each triad was a set of 3 elements that have similar properties (e.g.
Cl, Br and I; Ca Sr and Ba).
In 1863, John Newlands noted that when the known elements were written
in order of increasing relative atomic mass, every eighth element has
similar properties. He called this the Law of Octaves. (There were
only seven elements in each period at this time because the noble
gases had not been discovered yet). After 20 elements his table did
not make any sense, he had 2 elements in one space because the
relative atomic mass values that had been used were incorrect. He was
quite close to the right answer.
Six years later in 1869 professor Dimitri Mendeleev came up with a
periodic table that ours is based on today. A whole new group was
added as the noble gasses were found; all the gaps have been filled.
Elements are arranged in order of increasing atomic number, rather
than relative atomic mass. He amended some relative atomic masses and
he also left gaps for undiscovered elements. For the gaps in his
table, he predicted the properties of these undiscovered elements. He
predicted the properties of an element he called eka-aluminium. He was
proved right in 1875, the element was called gallium; its properties
are in excellent agreement with Mendeleev’s predictions.
Gallium is unusual because it has such a low melting point (29.78ºC).
In hot countries it becomes a liquid metal like mercury. It is also
unusual because of its high boiling point (2403ºC). It has the widest
liquid range of any element. It shares the same property as water for
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
We all know the saying, “Don’t judge a book by it’s cover.” Similarly, every element in the periodic table has its’ own story and its’ own unique meaning. However, the average high schooler simply associates these elements as something used in their chemistry classes. In fact, the elements seen on the periodic table actually have much more to do in our daily lives and in history than most people know. While giving a whole new perspective to the meaning of Chemistry, author Sam Kean successfully recounts the hidden tales through humor and wit in his bestselling novel The Disappearing Spoon: And Other True Tales of Madness, Love, and the History of the World from the Periodic Table of Elements. Specifically, Chapter 15, “An Element of Madness,” addresses the lives of several “mad scientists” associated with selenium, manganese, palladium, barium, and roentgenium that ultimately led to their downfall.
The Beryllium element, an alkaline earth metal which belongs to group II of the periodic table, was first discovered in 1798 by L.M. Vauquelin. Vauquelin,a French chemist, was doing work with aluminum and noticed a white powder that was nothing like that of aluminum or any of its derivatives. Vauquelin named this mystery powder, gluinium because of its sweet taste was like that of glucose. In 1828, Wohler, a German metallurgist reduced it to its metallic form and renamed it beryllium.(figure 2)
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. In 1803 this theory was finalised and stated that (1) all matter is made up of the smallest possible particles termed atoms, (2) atoms of a given element have unique characteristics and weight, and (3) three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules).
George Gamow, Ralph Alpher, Robert Hermen. "The Origin of Chemical Elements." [Online] 1 April 1948. .
The Periodic Table is based around the Atomic Theory. Firstly people believed that everything was made up the four elements Earth, Fire, Wind, and Water. This theory evolved into everything being made up of atoms. Breakthroughs throughout history such as the discoveries of the nucleus, protons, neutrons and electrons have pushed this theory forward to where it is today.
Dalton’s atomic theory says that each element contained its own number of atoms. Each element had its own size and weight. Dalton’s idea said that all things are made of small bits of matter this bits of matter where too small to be seen even with a microscope. Scientist began to think these small bits of matter where responsible for chemical changes. They thought that when these bits of matter combined a chemical change took place. Dalton assumed that there was a special pattern in the elements and was partly responsible for the periodic table.
Though many people fail to realize it, chemistry is a subject essential to everyday life, due to the fact that it is the branch of science that deals with the identification of the substances of which matter is composed. But what we must understand is that everything in the universe is composed of matter, hence chemistry is necessary in learning more about the world and universe that we live in. There are many careers and fields affiliated with chemistry that people pursue to learn more about the composition of the universe, but for now, let us examine the logistics of three of these careers. These three careers involving chemistry are geochemistry, environmental chemistry, and chemical engineering.
Chemistry is the most fascinating science to me. Chemistry applies to all things in the universe; living or non-living. Everything is made of elements which are made up of atoms of a certain atomic number. Thereafter I took AP Chemistry, I knew I had to choose a career in the field of chemistry. I understand and enjoy learning about chemistry. Chemistry is important, interesting, and ever expanding. Therefore, I must pursue a career in Chemistry.
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.
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...
Chemistry has lots of charming facts; one such is hetero cyclic compounds. Heterocyclic compounds are organic compounds that contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen or nitrogen as the heteroatom. The ring may be aromatic or non-aromatic. Every first step of life starts with hetero-cyclic compounds. Every man's potential to think, intelligence, behavior, character depends on his gene. The basic skeleton of the genetic material (DNA) is made up of heterocyclic compound like adenine, guanine, cytosine and thymine. Thus knowing about heterocyclic compound and its application is part of venturing human life. The different pharmacological activity of the different hetero cyclic compounds ring , from a last related to this moiety and screened them for their different pharmacological activities to get a molecule which have good pharmacological activity and lesser side effect. These pharmacological activities of new hetero cyclic derivatives this hetero cyclic has shown its importance as antibacterial, antifungal, anti-inflammatory, hypoglycemic, antidepressant, anti-malarial, analgesic, anticancer