... to LUMO (with retained opposite spins, i.e. S=0). Other models give qualitatively the same picture; e.g. the Huckel model for the electron system or more advanced semi-empirical models and data programs, or ab initio models (e.g. the Gaussian programmes of John Pople, Nobel Prize in Chemistry 1998),which has a more or less regular energy ladder for the filled orbitals followed by a ladder of empty orbitals ... . The total wave function for the many-electron system occupies a state (in the simplest model it is the product of all the one ... , takes place after photo-excitation to an upper...

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... bond that involves sharing a pair of electrons between atoms in a molecule. The two atoms have positive nuclei. They are both attracted to the same electron. In this way the two nuclei are held close to each other. Each atom will follow the octet rule – A full outer shell ( ... by a line drawn between the atoms. Hence a hydrogen molecule can be represented as H–H. Another example is when two chlorine atoms, with electron configurations of 2, 8, 7, combine to form a chlorine molecule, the chlorine atoms share a pair of electrons. In this way, each chlorine atom obtains a share in ... w...

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... up the sodium chloride (NaCl) for 5 minutes and discovered that nothing happened to it. Discussion Sodium chloride contains two charged particles, Na+ and Cl-. Cl- is missing one electron to get 8 electrons in its outer shell, and Na+ has one electron too much to reach its goals of 8 electrons. This creates an electrostatic attraction between the two particles, and Na+ gets an ... electron from Cl-. These ions will stay together by the electrostatic attraction because they are oppositely charged. This is called an ionic bonding, and in this case it is called NaCl. ... substance. As ex...

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... or more elements bounded together, so that they cannot be separated by physical means. Compounds are held together by ionic or covalent bounds. Be able to distinguish among proton, neutron, electron based on mass and charge properties. Be able to explain what an ion is and why one might result. Ion is and why one might result: When an atom loses ... a composite particle, belongs to the baryon group. Neutrons have about the same mass as protons but no electric charge, contribute to the mass of atoms but do not affect their chemistry. Electron Based on mass and charge properties...

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... , many scientists worked to formulate how the atom works. Which began in the early 1800's with John Dalton, to our current model of the electron cloud developed by Schrodinger. During this long process of the discovery the atom, took many models and scientists. The entire group of scientists who assisted ... he discovered negative and positive charged particles. He stated that the atom was made of smaller particles called, electrons and protons. In the discovery of the electron he used the Cathode-ray tube. As he researched he came up with a model of the atom, he stated that the atom was...

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... , many scientists worked to formulate how the atom works. Which began in the early 1800's with John Dalton, to our current model of the electron cloud developed by Schrodinger. During this long process of the discovery the atom, took many models and scientists. The entire group of scientists who assisted ... he discovered negative and positive charged particles. He stated that the atom was made of smaller particles called, electrons and protons. In the discovery of the electron he used the Cathode-ray tube. As he researched he came up with a model of the atom, he stated that the atom was...

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... , but no matter how hard you try, you could not outrun him/her? Well, this is the same dilemma that faces the electron and the PBG crystals. The electron is currently what a computer uses to transfer information. The PBG crystals are a new form of technology that can allow information to travel ... in sending the photon depends on a few different elements. The most important element is the elimination of many items used in transferring information via an electron. The electrons need a solution material in order to transfer from place to place. The most common solution is silicon. Silicon...

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... vocabulary) Atoms in compounds are held together by chemical bonds. Chemical bonds result from the shaping or transfer of valence electrons between pairs of atoms. Bonded atoms attain the stable electron configuration of a noble gas. The noble gases themselves exist as isolated atoms because that it their most stable condition For the representative elements, the # of valence electrons is = ... valence electrons. This arrangement constitutes the metallic bond. The valence electrons in metals are mobile and can travel from one end of a piece of metal to the other. This electron mobility ...

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... fraction of a second; then it is immediately drawn back toward the nucleus, to its original orbital. As it returns to its original orbital, the electron releases the extra energy in the form of a photon, in this case a light photon. The wavelength of the emitted light depends on how much energy ... is released, which depends on the position of the electron. Different kinds of atoms will release different sorts of light photons meaning the color of the light is determined by what kind of atom is excited ... higher energy levels. When the electrons return to their original energy level, t...

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... charged particles, there can be no electric force fields and thus no electromagnetic waves. What are electrons and protons? An electron is a particle with negative charge and not much mass. The positively charged proton exerts an invisible, attractive force on the electron -- an electric force. the electric force is like an invisible spring, but as the charges move farther apart, a weaker spring ... pulls them together.An electron's motion depends on both the force on the electron and its velocity, which are often in different directions. What is a Force field? In physics, a force field...

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... charge. By measuring the effect of an electric field on single drops of evaporating oil, Robert Millikan ingeniously was able to measure the charge of a single electron and then to determine it's mass. By the beginning of the twentieth century, relatively very little was known for certain about the structure of an atom. ... . This changed in 1897, when the British physicist J.J. Thomson was able to determine the ratio of electrical charge to mass for an electron using a cathode-ray tube. This ratio of 1.76*10^8 coulombs per gram, was what enabled Millikan to calculate the mass of a singl...

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• Grade Level: Undergraduate

... charge. By measuring the effect of an electric field on single drops of evaporating oil, Robert Millikan ingeniously was able to measure the charge of a single electron and then to determine it's mass. By the beginning of the twentieth century, relatively very little was known for certain about the structure of an atom. ... . This changed in 1897, when the British physicist J.J. Thomson was able to determine the ratio of electrical charge to mass for an electron using a cathode-ray tube. This ratio of 1.76*10^8 coulombs per gram, was what enabled Millikan to calculate the mass of a singl...

• Word Count: 579
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• Grade Level: Undergraduate

... . He discovered Thermal Expansion. Thompson, Becquerel, and Rutherford all worked in the same time period. Thompson's work was on the electron. He was the first to actually discover the electron. He also discovered the mass to charge ration. He discovered the electron in 1897-1899. Becquerel was a French physicist and won the Nobel Prize in 1903 for his discovery of radiation in 1896 ... ...

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... as protons. By no means we know that an atom carries no charge making it neutral. In the event that atoms share an electron pair this is called a covalent bond. Every atom grows more solid by sharing its uneven electron with the other. We shall discuss the polar and non-polar covalent bonds. Within a polar covalent bond, atoms of different elements do ... not install the same pull on shared electrons. The atom that receives the electron ends up with a slender negative charge making it electronegative. While non-polar method states that there is no difference in charge between to ends of...

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The identity of the electron goes back to 1752 when Benjamin Franklin's discovery set other scientists out trying to see if electrical energy could travel through gases other than the atmosphere. This was proven to ... discovered by Thomas, millikan calculated that the mass of a cathode ray particle was smaller than the smallest known atom, hydrogen. We now know that the cathode ray particle is an electron, and a cathode ray is a stream of electrons....

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... . Protons have a "positive" (+) charge. Electrons have a "negative" (-) charge. Neutrons are not charged, therefore they are neutral. The charge of one proton is equal in strength to the charge of one electron. When the number of protons in an atom equals the number of electrons, the atom has no charge, and is neutral. If there are more protons than electrons, the atom ... higher when they are arranged in a series. When multiple sources are arranged in parallel, the voltage stays almost the same as a single source. Resistance is a conductor's ability to slow down electron flow. Low resis...

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... nucleus contains positively charged particles called protons and uncharged particles called neutrons. The nucleus of an atom is surrounded by negatively charged particles called electrons. The negative charge of an electron is equal to the positive charge of a proton, and the number of electrons in an atom is usually equal to the number of protons. When an outside force upsets the ... balancing force between protons and electrons, an atom may gain or lose an electron. When electrons are "lost" from an atom, the free movement of these electrons constitutes an electric current. Electricit...

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... A) The resistance will be calculated in Ohms, the potential difference in volts, and the current in amps. Plan Apparatus too be used: 1. Power Pack (used to control the flow of electron through the circuit) 2. Amp metre 3. Voltmeter (used to calculate the value of resistance) 4. Resistance wire (the length of which will be used to change the amount of resistance) 5. Crocodile clips ... clip) 2. Attach the crocodile clips to the resistance wire at the appropriate place, so that the wire is 20mm long. 3. Turn on the power pack to allow the flow of electron through the circuit. 4. Ensure t...

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... made quite clear when we used the donut to follow the more negative charge to the negative supply. Questions: 1) The field lines went from positive to negative and on both configurations that meant that the field lines traveled from right to left. 2) The electric field is more intense at two specific points. These are visible by looking at the graphs and ... ...

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... electrons. This experiment concluded that electrons are present in atoms of all elements and that they have a very large charge-to-mass ratio. Robert A. Millikan measured the charge of the electron. Based on his measurements two inferences were made about an atoms composition. 1.) Because atoms have no charge, there must be a positively charged particle canceling out the negative charge; and 2.) Atoms ... ...

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... are ductile, malleable, tend to be shiny, most are solid at room temperature, and are good conductors of heat and electricity. The electrical conductivity of a metal is related to the electron structures of metal atoms. Most metals have fewer than 4 valence electrons. These electrons are free to move throughout the crystalline lattice formed by the metal atoms. The electrons move randomly ... ...

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We were able to ignore the terms on the right side of the equation because we know mass is conserved within the reaction. Also the conservation of atoms tells us that the ratio of moles of copper chloride to aluminum is constant. So given the amount of copper chloride that reacted, we could find the amount of aluminum that reacted. If all the aluminum dissolved and the liquid was still blue, we would know that aluminum was the limiting reagent. We would also be able to calculate the mass of the original aluminum wire if we were able to measure the mass of the leftover copper. By finding the ma...

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... be separated through the application of an electric current. Electrophoresis was developed by Arne Tiselius. The process is used in medicine and biochemistry (science concerned with the organic and physical chemistry) to separate, identify, and measure the amount of various proteins. Electrophoresis is an analytical method frequently used in molecular biology (study of life processes) and medicine. It is applied for ... ...

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... be separated through the application of an electric current. Electrophoresis was developed by Arne Tiselius. The process is used in medicine and biochemistry (science concerned with the organic and physical chemistry) to separate, identify, and measure the amount of various proteins. Electrophoresis is an analytical method frequently used in molecular biology (study of life processes) and medicine. It is applied for ... ...

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Chemistry Coursework Electrolysis of Sodium Chloride (NaCl) Aim: To find out how the exchange of NaCl will affect the current. Preliminary Test: To make sure we understand how the experiment is going to work, we need to carry out an initial test. This will enable us to go through ...

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