The History of the Atom Hypothesis according to Aristotle (350 BC): All matter consists of the elements earth‚ air‚ fire‚ and water. Experiment: A tree grows from the earth as water is added. The tree is then set on fire in an effort to form new elements. 1. What kind of results would be observed from this experiment? Fire‚ ash (earth)‚ smoke (air) 2. Would these observations support or reject the hypothesis? Explain. Support. No elements have been produced that are something other than
Free Atom Electron Electric charge
image‚ or scanned and pasted into this document. Questions 1. An electron that has left the parent atom is called a ___free___ electron. 2. What is the voltage between two points if 100 J of energy is used to move 20 C between the points? V= WQ = 100J20C =5JC =5 V 3. How many electrons are there in a charge of 0.005 C? 3.12 ×1016 4. How much energy is required to move a charge containing 2.5x1013 electrons through a potential difference of 12 Volts? 43μJ 5. A charge of
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represent the most straightforward trend in properties. As the atomic number of the elements increases across a period‚ the trend is from metallic to a non-metallic character. Electronegativity is a measure of an element’s ability to attract a shared electron pair to itself. Metals have a smaller electronegativity than 1.7 and non metals greater than 2.4. As the size of an atom decreases the electronegativity increases; so the value increases across a period and decreases down a group. Melting Points:
Free Periodic table Atom Chemical element
rising to 1.5/1 for elements having atomic numbers between 20 and 83. An understanding of the Belt of Stability will allow you to predict how unstable nuclides will decay. The typical modes of radioactive decay are alpha decay‚ beta decay and electron capture (or positron emission). During alpha decay‚ the mass number of the nuclide decreases by 4 units and the number of protons decreases by 2. This type of decay is associated with heavy‚ unstable nuclides. Since no stable isotopes exist
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– 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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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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tire pressures are off. The first thing that I would like to do is explain what electricity is in an automobile. Electricity is the worlds most widely used source if energy. Electricity is the flow of electrons through a conductor to eventually be used to supply a load of some sort. The electrons flow from positive to negative. In order to understand how an electric charge moves from one atom to another‚ you need to learn a little about atoms. Everything that surrounds us is made of atoms; every
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electric charge in several ways. These include the quantities Current‚ Voltage and Power. Current * Current (I) is the rate of flow of Charge Carriers‚ such as electrons. Current is usually thought of as moving in the direction of positive charge‚ so from the positive power supply to the negative. However‚ since in metals it is electrons that carry electric charge‚ the actually flow is opposite to the way in which we think of it. * Current it the amount of Charge‚ Q that passes a point in
Free Atom Electron Chemical bond
particles. The constituent particles of an atom are the electron‚ the proton and the neutron. However‚ the hydrogen-1 atom has no neutrons and a positive hydrogen ion has no electrons. The electron is by far the least massive of these particles at 9.11×10−31 kg‚ with a negative electrical charge and a size that is too small to be measured using available techniques.[46] Protons have a positive charge and a mass 1‚836 times that of the electron‚ at 1.6726×10−27 kg‚ although this can be reduced by
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from the nucleus to the valence electron gets weaker. The valence electron is loosely held and it is easy for the elctron to be released to form stable octet lectron arrangement. The reactivity of G1 is the tendency of the atom to release elctron to form stable electron arrangement. The easierm the atom releases electron‚ the more reactive it is. ELECTROPOSITIVITY The electropositivity of G1 is the tendency of the atom to release electron to form stable electron arrangement. As the size increases
Free Atom Electron