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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Grades K-5 Pencil Electrolysis Introduction: The process by which we separate the elements hydrogen and oxygen from water is called electrolysis. The word "lysis" means to dissolve or break apart‚ so the word "electrolysis" literally means to break something apart (in this case water) using electricity. It is difficult to break up water into it’s elements lots of energy is needed to do that. Through a chemical means though‚ we can separate the compound of water into the elements that combine to
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oxygen atom taking the pair of electrons from the pi bond and results in a negative charge on oxygen and a positive charge on carbon. The positive charge on carbon is then stabilized by the donation of a lone pair of electrons from oxygen‚ which is attached to both of the carbonyl groups in acetic anhydride‚ and results in the formation of an O=C bond with the oxygen containing a positive charge. The formation of the oxygen with the positive charge causes the electrons in C-O bond to be pulled more
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Chapter 1 * What is Chemistry? -it is the study of the composition of substances and the changes they undergo. * What are the 5 branches of chemistry? * Organic chemistry‚ inorganic chemistry‚ analytical chemistry‚ physical chemistry‚ biochemistry. * What is the difference between a theory and law? -a theory is a thoroughly tested explanation of why experiments give certain results. A scientific law is a concise statement that summarized the results of a broad spectrum of observations
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CHEMISTRY 17 1ST LONG EXAM REVIEWER I. ELECTRONIC STRUCTURE OF ATOMS -arrangement of atoms’ electrons -the number of electrons in an atom -distribution of electrons around the nucleus and their energies • ATOMS *Billiard Ball Model (JOHN DALTON) *Plum Pudding Model (JOSEPH J. THOMPSON) *RUTHERFORD’s Model of Atom -atoms are tiny‚ hard‚ indivisible spheres -electrons (negative charge) occupy the atom - Atom is mostly empty space with a dense nucleus • PROBLEMS with Rutherford’s Model
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positively charged entity that contains randomly dispersed (negative) electrons within it. It is called the plum pudding model because the electrons in the positively charge cloud resemble raisins in a pudding. Thomson realized that all atoms must contain electrons‚ and since the atoms had a neutral charge‚ they must also include protons. This led him and other to think of the atom as a positively charged cloud with electrons randomly scattered in it. Rutherford later found this model to be false
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Experiment” in which Jonsson shot electrons through two holes to observe how subatomic particles react in stress. As you would imagine‚ an electron couldn’t possibles go through both holes at the same time... or could it? Jonssons discovery was a major break through in quantum physics. Heres the peculiar part‚ when you were directly observing the electrons‚ they would go through either one hole or the other‚ but the what we couldn’t see‚ the results showed electrons traveling through both holes‚ leading
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