– PHYSICIST WHO DISCOVERED ELECTRONS (e-) * The cathode ray * “plum pudding model” aka Chocolate Chip Cookie or Blueberry Muffin Model of an atom with electrons * Ernest “radioactive man” Rutherford (1907) – “gold foil experiment” * Electron cloud theory * Discovered that the nucleus has a positive charge * Most of the atom is empty space * Neils Bohr – planetary model (2D) worked with hydrogen * Worked with Rutherford * Electrons have specific orbitals where
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magnet and moved toward the positive magnet‚ leading to the discovery of negatively charged electrons. From this experiment‚ he was also able to conclude that electrons have mass based on how they swirled in the tube. The first identification of a subatomic particle inspired Thomson to create his plum-pudding model. This model featured the atom as a positively charged‚ solid sphere with randomly distributed electrons throughout it like chocolate chips in a chocolate chip cookie. However‚ the discoveries
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known to contain other particles as well. Yet Thomson’s bold suggestion that cathode rays were material constituents of atoms turned out to be correct. The rays are made up of electrons: very small‚ negatively charged particles that are indeed fundamental parts of every atom. Modern ideas and technologies based on the electron‚ leading to television and the computer and much else‚ evolved through many difficult steps. Thomson’s
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surface of a metal. If only 1 of each 5 × 109 incident photons is absorbed and causes an electron to be ejected from the surface‚ the total photocurrent in the circuit is ________. 3. Light of wavelength 330 nm falling on a piece of metal ejects electrons with sufficient energy which requires voltage V0 to prevent a electron from reading collector. In the same setup‚ light of wavelength 220 nm‚ ejects electrons which require twice the voltage V0 to stop them in reaching a collector. Find the numerical
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effect? The photoelectric effect is when a clean metal surface emits electrons after light‚ especially ultraviolet‚ has been shone on at it. This happens because of a process called photoelectric emission whereby a single photon package of electromagnetic energy‚ called a quantum‚ is absorbed by metal surfaces. This energy is then transferred to one single electron which can then be released by the metal and that released electron is known as a photoelectron. The effect was first absorbed by German
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the Nucleus The nucleus contains both Protons and neutrons The negatively charged particles surrounding the center are called Electrons (3^H)‚ an isomer‚ differs from (1^H) in that: 3^H has 2 more neutrons than 1^H Nitrogen has 7 electrons and thus can form a maximum of ___ covalent bonds with other elements 3 Carbon has 6 electrons while hydrogen has 1 electron. How many covalent bonds can form between a carbon atom and hydrogen atoms 4 In the lab you are culturing human cells in order
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at the end of 19th century‚ experimental investigations on conduction of electricity (electric discharge) through gases at low pressure in a discharge tube led to many historic discoveries. The discovery of X-rays by Roentgen in 1895‚ and of electron by J. J. Thomson in 1897‚ were important milestones in the understanding of atomic structure. It was found that at sufficiently low pressure of about 0.001 mm of mercury column‚ a discharge took place between the two electrodes on applying the
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general‚ there are three types of chemical bonds: I. Ionic bond: Transfer of electrons from one atom to another. Seen primarily in M + NM. Bond is an electrostatic attraction of of a _______for an ______. II. Covalent bond: Results from a ________ of outermost electrons. A. __________covalent: ______ sharing of electrons. Observed in two of the same NM’s or in C-H bonds. B. ______covalent: ________ sharing of electrons. Observed in two different NM’s (not C-H bonds) III. Metallic bond: Chemical
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ELECTRICITY - A Secondary Energy Source A Secondary Source The Science of Electricity How Electricity is Generated/Made The Transformer - Moving Electricity Measuring Electricity energy calculator links page recent statistics A SECONDARY SOURCE Electricity is the flow of electrical power or charge. It is a secondary energy source which means that we get it from the conversion of other sources of energy‚ like coal‚ natural gas‚ oil‚ nuclear power and other natural sources‚ which are called primary
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stable. Consisting of protons and neutrons‚ they are unaffected by chemical reactions and have remained the same since they were formed. However‚ some nuclei are unstable and spontaneously release energy in the form of a Helium nucleus (α Alpha)‚an electron (β Beta) and γ Gamma rays. These nuclei are known as radioactive and it’s not possible to predict when a particular radioactive nucleus will emit this energy but a large number of materials are said to have a ‘half life’. The half life is the time
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