poor conductor of electricity. If the electrons in an atom can’t be moved from their orbits at all‚ the material is an insulator. If at least some of the electrons can be moved‚ the material is a resistor. Two of the best-known conductors of electricity are silver and copper. The atomic structures of the silver and copper atom are compared in Figure 6. Note that both atoms have only one electron in the outermost orbit. This makes silver and copper excellent conductors of electricity. Silver
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nucleus contains positively charged protons and uncharged neutrons. The electron cloud is composed of negatively charged electrons. Elements in the same row are similar in size. Elements in the same column have similar electronic and chemical properties. An s orbital has a sphere of electron density and is lower in energy than the other orbitals of the same shell. A p orbital has a dumbbell shape and contains a node of electron density at the nucleus. It is higher in energy than an s orbital.
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c. Insulator • Number of valence electrons is 1-3 with very high conductivity • Number of valence electrons is 4 with intermediate conductivity • Number of valence electrons is 5-8 with very low conductivity Semiconductor Conductors • Has more electrons that are free to move • Supports charge carriers to flow • Support flow of electricity • Has very low resistance allowing easy flow of electron current • Has less than 4 valence electrons – Examples: metals‚ electrolytes and
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MANIPULATIONS: Cathode rays can be manipulated in a number of ways: 1) SPEED a. The speed the rays travel can be changed by changing the voltage between the anode and cathode. The voltage change changes the potential energy of the electrons. As it travels between the anode and the cathode‚ this energy is transformed into kinetic energy‚ therefore changing the speed of the particles. 2) NUMBER OF RAYS b. The number of cathode rays can be further manipulated by the introduction
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a molecule or ion‚ follow these steps: •Step 1: Count up the number of valence electrons for each atom‚ and total them up to give the total number of electrons for the molecule. If the molecule is an ion‚ include that charge in the count. For example‚ for a +1 ion‚ subtract one electron‚ and for a -2 ion add two electrons to the total count. (For more information about how to count the number of valence electrons per atom‚ see the related questions link to the left of this answer). •Step
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predicted by Valence-Shell Electron-Pair Repulsion (VSPER) theory. The following are the sets of rules summarizing thsi theory: ● Consider molecules and ions where two or more atoms are bonded to a central atom. ● The electron pairs in the valence shell of the central atom are assumed to position as far apart as possible because electron pair repels one another. The shape of the molecule or ion is a result of the electron-pair repulsion. ● All the valence-shell electron pairs of the central atom
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Flame colours are produced from the movement of the electrons in the metal ions present in the compounds. For example‚ a sodium ion in an unexcited state has the structure 1s22s22p6. When you heat it‚ the electrons gain energy and can jump into any of the empty orbitals at higher levels - for example‚ into the 7s or 6p or 4d or whatever‚ depending on how much energy a particular electron happens to absorb from the flame. Because the electrons are now at a higher and more energetically unstable
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Free Electron model can. Explains the effects of the temperature‚ impurities‚ and deformation on Electrical Conductivity in which the Drude Model can’t explain. List two aspects of materials behaviour that the Drude and QFE models can’t explain but that Band Theory can. The Band Theory can explain why the outer electrons become delocalised and the semi conductivity. [2 marks for each part] 2 Using the Drude model‚ for platinum‚ calculate the number of delocalised electrons per
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increase the voltage of our product. The zinc can produce electricity because of the chemical reaction it occurs when it is soaked in vinegar’s acetic acid‚ the zinc is dissolved to produce hydrogen gas; while the copper’s use is only to move the electrons throughout the entire circuit and connect it to the battery powered object. The main idea we took on our research and personal experiences is that when more batteries are connected‚ more voltage are produced. Our design is to connect one container
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Chapters 7&8 Gauge Sheet 7.1- Ions To find the number of valence electrons in an atom of a representative element‚ simply look at its group number. Atoms of metals tend to lose their valence electrons‚ leaving a complete octet in the next-lowest energy level. Atoms of some non-metals tend to gain electrons or to share with another non-metal to achieve a complete octet. The gain of negatively charged electrons by a neutral atom produces an anion. 7.2- Ionic Bonds and Ionic Compounds Although
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