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John Dalton's Theory Of Chemistry

explanatory Essay
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973 words
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Ch 3 Outline: Pg. 61 Once upon a time a Chinese cook combined charcoal with two other common Chinese ingredients. It ended with an explosion of sparks. Even if that story is false, most everyone agrees that fireworks originated from China. Pg. 62 This page includes an image of 48 iron atoms forming a “corral” around a single copper atom. Pg. 63 Atoms are like a wrapped birthday present, you want to investigate it, but you cannot see it easily. Pg. 64 The term atoms means “cannot be divided”. Early philosophers used reasoning, debating, and discussion to prove their theories. Chemistry is the study of matter. Little was known about atoms even 500 years ago. Even today, with our most powerful microscopes, we are not able to see atoms. It is …show more content…

In this essay, the author

  • Explains how a chinese cook combined charcoal with two other common chinese ingredients and it ended with an explosion of sparks. although the story is false, most people agree that fireworks originated from china.
  • Explains that this page includes an image of 48 iron atoms forming a "corral" around one copper
  • Explains that atoms are like a wrapped birthday present, you want to investigate it, but you cannot see it easily.
  • Explains that the term atoms means "cannot be divided". early philosophers used reasoning, debating, and discussion to prove their theories. chemistry is the study of matter.
  • Explains that john dalton combined the idea of atoms and elements together in the nineteenth century.
  • Explains that a piece of metal that can conduct energy is called an electrode.
  • Explains that negatively charged particles are now called electrons. particles smaller than the atom do exist. opposite charges attract each other.
  • Explains thomson's model of an atom as a sphere of positive charge wit the negatively charged electrons were spread evenly among the positive charges.
  • Explains that the proton is a positively charged particle present in the nucleus of all atoms, while the rest of each is empty space occupied by its almost mass less electrons.
  • Explains that neutrons have the same mass as protons and are electrically neutral. they don't respond to magnets or cause fluorescent screens to light up.
  • Explains that electrons are in constant, unpredictable motion and can't be described easily by an orbit. it is impossible to know the precise location of an electron at any particular moment.
  • Explains that the electron cloud is the region surrounding the nucleus in which electrons travel. they are attracted to the positive charges of the protons.
  • Explains that scientists make models of things they can't see by doing experiments, gather as much data as possible, and then try to fit the information together into some kind of pattern.
  • Explains that atoms of an element are identified by the number of protons because this number never changes.
  • Explains that mass number is the number of protons plus neutrons in an isotope. radioactive decay releases nuclear particles and energy.
  • Explains that an alpha particle consists of two protons and two neutrons. energy and particles are called nuclear radiation.
  • Explains that a beta particle is an electron that comes from the nucleus, not the electron cloud. half-life is the amount of time it takes for half of an element of decay.
  • Explains radioactive decay of unstable atoms goes on at a steady pace, unaffected by conditions such as weather, pressure, magnetic, or electric fields, and even chemical reactions.
  • Explains that scientists use carbon-14 to detect how old a living (but now dead) organism is. radioactive decay produces radioactive waste.
  • Explains that tracer elements are synthetic. elements with atomic numbers 93 to 112 and 114 have been made in this way.
  • Explains that small amounts of radioactive substances, called radioisotopes, can be used to diagnose disease.
  • Explains that isotope iodine-131 is used to diagnose thyroid problems. tracer elements such as phosphorus-32 are injected into the root system of a plant.
  • Describes how physicist henri becquerel was unable to complete the day's planned work requiring the sun as the primary energy source. he later discovered uranium emits radiation.

65 During the eighteenth century scientists began debating the existence of atoms again. All matter is made of elements. An element is matter made of atoms of only one kind. John Dalton combined the idea of atoms and elements together in the nineteenth century. His ideas: 1. Matter is made up of atoms, 2. atoms cannot be divided into smaller pieces, 3. all the atoms of an element are exactly alike, and 4. different elements are made of different kinds of atoms. John Dalton’s theory was tested in the later half of the nineteenth century. Pg. 66 A piece of metal that can conduct energy is called an electrode. One electrode (the cathode) has negative charge; another (anode) has a positive charge. Pg. 67 Negatively charged particles are now called electrons. Particles smaller than the atom do exist. Opposite charges attract each other. Pg. 68 Thomson pictures a model of an atom as a sphere of positive charge wit the negatively charged electrons were spread evenly among the positive charge. Not all atoms are neutral. The number of electrons within an element can vary. Alpha particles are fast-moving, positively charged bits of matter. Pg. 69 Some alpha particles were veering off at large angles during Rutherford’s experiment. Pg. 70 Large changes in direction were not expected. A proton is a positively charged particle present in the nucleus of all atoms. The rest of each atom is simply empty space occupied by the atom’s almost mass less …show more content…

79 The radioactive decay of unstable atoms goes on at a steady pace, unaffected by conditions such as weather, pressure, magnetic, or electric fields, and even chemical reactions. Pg. 80 Scientists use Carbon-14 to detect how old a living (but now dead) organism is. This is also known as radioactive decay. Radioactive decay produces radioactive waste. Pg. 81 Tracer elements are synthetic. Elements with the atomic numbers 93 to 112, and 114 have been made in this way. Pg. 82 Very small amounts of radioactive substances, called radioisotopes or “tracer elements”, can be used to diagnose disease. Pg. 83 Isotope iodine-131 is used to diagnose problems with the thyroid. Tracer elements such as phosphorus-32 are injected into the root system of a plant. Pg. 84 The decay rates of most radioactive isotopes range from milliseconds to billions of years. Pg. 85 Using scientific methods determine whether you can predict individual atom half-lives. Pg. 86 One cloudy day in the spring of 1896, physicist Henri Becquerel was unable to complete the day’s planned work requiring the Sun as the primary energy source. He later discovered uranium emits

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