was one experiment conducted by Hertz‚ the photoelectric effect‚ which could not be explained by considering light to be a wave. Hertz observed that when certain metals are illuminated by light or other electromagnetic radiation‚ they lose electrons. Suppose we set up an electric circuit. In this circuit the negative terminal of a battery has been connected to a piece of sodium metal. The positive terminal of the battery is connected through a meter that measures electric current‚ and to
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Lewis Structure Review How To Write Lewis Structures 1. Determine the total number of valence electrons from all of the atoms in the molecule or ion. • Add one electron for each unit of negative charge. • Subtract one electron for each positive charge. 2. Write the correct skeletal structure. • For molecules of the formula ABn‚ place the least electronegative element in the center‚ and the more electronegative elements in the terminal positions. • H is always a terminal atom‚ and NEVER a central
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to light reflection. 2. Electron Double Slit Experiment a. Electrons are fired (possibly one at a time) toward a screen with two slits and each electron that passes through leaves a dot on a film plate. The dots accumulate on specific places‚ as shown in the diagram below‚ separated by b lank zones. Therefore‚ there is a certain probability that an electron may land on C‚ E‚ G… and zero probability that it may go to D‚ F… b. The probability that an electron may land on some point on
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Onion Distilled Water Apparatus: Microscope Microscope slides & cover slips Tile Knife Tweezers Pasteur Pipettes Assignment: I was given the onion once it had been chopped up on the tile‚ ready for me to peel back the skin I required using the tweezers. I then placed piece of onionskin onto the microscope slide‚ making sure there were no folds or creases‚ and put a drop of iodine onto the slide as well‚ to view through the microscope. On my first try the onion folded so I
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Neutron # # of Electrons Mass Number Charge Ar 19 31 17 18 35 20 18 3+ 40 3. In your own words‚ explain Thomson’s and Rutherford’s contribution to the atomic theory. Give sketches to substantiate your answer. 4. Explain how Bohr contributed in defining the structure of the atom. 5. Magnetic resonance imaging (MRI) is a powerful diagnostic tool used in medicine. The imagers used in hospitals operate at a frequency of 400 MHz (1 MHz = 106 Hz). Calculate: (a) The wavelength
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between electrons and nuclei‚ or as the result of a dipole attraction. The strength of chemical bonds varies considerably; there are "strong bonds" such as covalent or ionic bonds and "weak bonds" such as dipole–dipole interactions‚ the London dispersion force and hydrogen bonding. Since opposite charges attract via a simple electromagnetic force‚ the negatively charged electrons that are orbiting the nucleus and the positively charged protons in the nucleus attract each other. Also‚ an electron positioned
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characteristics of water are a result of the interactions between the outermost electrons of the constituent hydrogen and oxygen atoms. They are involved in a chemical process known as bonding. In chemistry there are various types of bonding. They are all a result of electrons interacting with each other. Atoms interact by transferring‚ sharing or rearranging their electrons in a way that allows them to achieve a full shell of electrons which makes the atom stable. In compounds‚ there are two main types
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……zero……….. charge. c) An electron has ………negative…….. charge. d) A proton and an electron have ……opposite……….. and ………equal…….. charge. 2. Complete the following sentences using words from the list below. electron(s) ion(s) neutron(s) nucleus (nuclei) proton(s) a) Every atom contains a ……nucleus……….. which is positively charged. e) The nucleus of an atom is composed of ………protons…….. and ………neutrons……... f) The ……electrons……….. in an atom move about
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CChemistry Exam #2 Study Guide (10/07/12) I. Bonding a. Ionic Bonding i. Electrons are transferred ii. Ions are held together by electrostatic force b. Covalent Bonding iii. Electrons are somehow shared iv. Electrons are attracted to nuclei (shared) II. Electronegativity c. The ability of an atom in a molecule to attract shared electrons to itself d. Measured on Pauling Scale e. Most electronegative: Fluorine. Then
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When a metallic substance shares electrons with a non-metal substance it forms covalent bonds‚ which make molecules. The metal becomes positively charged atoms‚ which means that the number of electrons is never less than the number of protons. Non-metals become negatively charged atoms‚ and now the number of electrons is more than the number of protons. When atoms share electrons of nonmetals then a covalent bond is formed inside the molecule. Monatomic elements are elements that only contain one
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