Etymology The name atom comes from the Greek ἄτομος (atomos‚ "indivisible") from ἀ- (a-‚ "not") and τέμνω (temnō‚ "I cut")‚[3] which means uncuttable‚ or indivisible‚ something that cannot be divided further.[4] The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers. In the 18th and 19th centuries‚ chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods
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baryta or BaO. But it was discovered in 1779 by Carl Scheele. Barium is classified as an alkaline-earth metal. Its atomic number is 56 and it is the fifth element in group 2.Natural Barium is made up of a mixture of seven stable isotopes‚ there are thirteen radioactive isotopes known to exist. Barium has never been found in nature in its pure form. When Scheele discovered barium in the 1700’s he could not isolate it he could only isolate the barium oxide. Another person to isolate the barium oxide was
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Hershey and Chase designed an experiment in which they could label protein or DNA and then track which entered the E. coli cell during infection. They grew one batch of T2 phage in the presence of radioactive sulfur‚ marking the proteins but not DNA. They grew another batch in the presence of radioactive phosphorus‚ marking the DNA but not proteins. They allowed each batch to infect separate E. coli cultures. Shortly after the onset of infection‚ they spun the cultured infected cells in a blender
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Chp. 4 Biology Study Guide Page 1 8/30/2011 BIOLOGY STUDY GUIDE CHAPTER 4– THE CHEMICAL BASIS OF LIFE Matter = anything that takes up space and has mass (major types of matter = solid‚ liquid‚ and gas) Any type of matter is made of one or more elements. o Element = a substance that cannot be broken down into other substances by regular chemical processes. (examples: gold‚ silver‚ mercury‚ etc.) There are approximately 25 elements necessary for life. • Examples: oxygen‚ carbon‚ hydrogen‚
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of the most famous scientists that ever lived. Her contributions such as the discovery of Radium and other key elements help us out every day‚ especially when getting an X-ray. Marie Curie is known to the world as the scientist who discovered radioactive metals i.e.‚ Radium and Polonium. Born and Death: Marie Curie was born November 7‚ 1867 in Poland and died on July 4‚ 1934. Her full name is Marie Sklodowska Curie. Personal life: As a child‚ Marie Curie amazed people with her great memory
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Chapter 1 * What is Chemistry? -it is the study of the composition of substances and the changes they undergo. * What are the 5 branches of chemistry? * Organic chemistry‚ inorganic chemistry‚ analytical chemistry‚ physical chemistry‚ biochemistry. * What is the difference between a theory and law? -a theory is a thoroughly tested explanation of why experiments give certain results. A scientific law is a concise statement that summarized the results of a broad spectrum of observations
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professor at McGill University‚ Rutherford does his investigations into the disintegration of the elements‚ and the chemistry of radioactive substances that gets him to earn the Nobel Prize in Chemistry 1908. Rutherford ’s research‚ and work done under him as laboratory director‚ established the nuclear structure of the atom and the essential nature of radioactive decay. Radioactive decay is the process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles. This emission
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repel. 7. J.J Thomson: Cathode ray tube -Discovered and named the electron (e-) 8. Henri Bequerel: discovered that uranium is radioactive Radioactivity = spontaneous emission of radiant E from an element as its nucleus decays. Radioactivity does not come from stable elements. 9. Marrie & Pierre Curie: Discovered 2 radioactive element Po(polonium) and Ra (Radioactive) 10. Ernest Rutherford: British scientist who discovered 3 kinds of radioactivity. Alpha: 2 plus charge & heaviest/ 3 is the slowest
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“Radiometric age-dating is based on the fact that every radioactive element decays. The original or “parent” element emits radiation and particles until the loss thereof transforms it into a stable “daughter” element. A series of transformations into other radio-active elements marks its unparalleled pattern and rate of decay until it reaches stability (Think Quest).” “The decay of radioactive elements occurs at different rates‚ depending on the specific isotope. These rates are stated in terms of half-lives
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Assignment 02/08/2010 The Process of Science a. Chapter 2: Question 11 How might you use a radioactive isotope to find out whether the oxygen in CO2 comes from sugar or oxygen gas? I would substitute with a radioactive isotope of oxygen and run the reaction. Upon observation of the result‚ the oxygen came from what was used if the carbon dioxide is radioactive. If the carbon dioxide is not radioactive‚ then it came from the sugar. b. Chapter 3: Question 11 What would you tell the food
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