Definition and Properties of Metallic Bonding

A metallic bond is a type of chemical bond formed between positively charged atoms in which the free electrons are shared among a lattice of cations. In contrast, covalent and ionic bonds form between two discrete atoms. Metallic bonding is the main type of chemical bond that forms between metal atoms. MARK GARLICK/SCIENCE PHOTO LIBRARY / Getty Images Metallic bonds are seen in pure metals and alloys and some metalloids. For example, graphene (an allotrope of carbon) exhibits two-dimensional metallic bonding. Metals, even pure ones, can form other types of chemical bonds between their atoms. For example, the mercurous ion (Hg22) can form metal-metal covalent bonds. Pure gallium forms covalent bonds between pairs of atoms that are linked by metallic bonds to surrounding pairs. How Metallic Bonds Work The outer energy levels of metal atoms (the s and p orbitals) overlap. At least one of the valence electrons participating in a metallic bond is not shared with a neighbor atom, nor is it lost to form an ion. Instead, the electrons form what may be termed an electron sea in which valence electrons are free to move from one atom to another. The electron sea model is an oversimplification of metallic bonding. Calculations based on electronic band structure or density functions are more accurate. Metallic bonding may be seen as a consequence of a material having many more delocalized energy states than it has delocalized electrons (electron deficiency), so localized unpaired electrons may become delocalized and mobile. The electrons can change energy states and move throughout a lattice in any direction. Bonding can also take the form of metallic cluster formation, in which delocalized electrons flow around localized cores. Bond formation depends heavily on conditions. For example, hydrogen is a metal under high pressure. As pressure is reduced, bonding changes from metallic to nonpolar covalent. Relating Metallic Bonds to Metallic Properties Because electrons are delocalized around positively charged nuclei, metallic bonding explains many properties of metals. ImageGap / Getty Images Electrical conductivity: Most metals are excellent electrical conductors because the electrons in the electron sea are free to move and carry charge. Conductive nonmetals (such as graphite), molten ionic compounds, and aqueous ionic compounds conduct electricity for the same reason—electrons are free to move around. Thermal conductivity: Metals conduct heat because the free electrons are able to transfer energy away from the heat source and also because vibrations of atoms (phonons) move through a solid metal as a wave. Ductility: Metals tend to be ductile or able to be drawn into thin wires because local bonds between atoms can be easily broken and also reformed. Single atoms or entire sheets of them can slide past each other and reform bonds. Malleability: Metals are often malleable or capable of being molded or pounded into a shape, again because bonds between atoms readily break and reform.  The binding force between metals is nondirectional, so drawing or shaping a metal is less likely to fracture it. Electrons in a crystal may be replaced by others. Further, because the electrons are free to move away from each other, working a metal doesnt force together like-charged ions, which could fracture a crystal through the strong repulsion. Metallic luster: Metals tend to be shiny or display metallic luster. They are opaque once a certain minimum thickness is achieved. The electron sea reflects photons off the smooth surface. There is an upper-frequency limit to the light that can be reflected. The strong attraction between atoms in metallic bonds makes metals strong and gives them high density, high melting point, high boiling point, and low volatility. There are exceptions. For example, mercury is a liquid under ordinary conditions and has a high vapor pressure. In fact, all of the metals in the zinc group (Zn, Cd, and Hg) are relatively volatile. How Strong Are Metallic Bonds? Because the strength of a bond depends on its participant atoms, its difficult to rank types of chemical bonds. Covalent, ionic, and metallic bonds may all be strong chemical bonds. Even in molten metal, bonding can be strong. Gallium, for example, is nonvolatile and has a high boiling point  even though it has a low melting point. If the conditions are right, metallic bonding doesnt even require a lattice. This has been observed in glasses, which have an amorphous structure.

The Goal Of The American Revolution - 1964 Words

While the goal of the American Revolution was great in importance, the nation hardly had the means in order to properly fight for it. At the time, most of soldiers were untrained farmers that served in local militia units for some times before returning to work the land. As a result, despite the great number of Patriots, General Washington had only roughly 20,000 troops under his control at a time. Even then, the army lacked greatly in supplies and equipment, and many of the soldiers pay was delayed. Their opponent, Britain, on the other hand was well equipped military-wise with leading naval power, trained foot soldiers, and support from the American Indians who were promised land for their help as well. The Americans certainly realized the position they were in and the large disadvantage they had, so gaining support by any means was a necessity but the only help they could hope for was from other European powers. Thus while the Revolutionary War was fought for independence, there w as a similar war going on to fight for the support they needed. While the most notable help would have come from larger countries with extensive military knowledge, there was little hope of gaining such support in the early days of the revolution. Therefore, serving as sort of diplomat, Benjamin Franklin wrote to several military men that he felt would be able to help the American cause. The first, Tadeusz KoÅ›ciuszko, a Polish born military engineer and a man of revolutionary aspirations feltShow MoreRelatedEssay on Revolutionary characters1294 Words   |  6 PagesAdam Ferguson, and lastly Lord Kames. This social theory was that there were many levels of civility in a society. These levels were hunting, pasturage, agriculture, and commerce. One example of the first level which is hunting is the the Native Americans. The excepted social process is that a country was to go through all of these levels by starting out on hunting and eventually the society would mature and work its way up to the point of being a commercially based society. Now t his process helpedRead MoreThe American Revolution and Indias Independence Movement Essays1455 Words   |  6 PagesIndian and American human societies. All types of governments – from local politics to federal bureaucracies to huge empires – maintain their authority through specific techniques, including fostering a shared identity (nationalism), developing economic interdependence, and sometimes using overt force. Challenges to that authority through violent and nonviolent revolution can have significant consequences, including the collapse and replacement of whole systems of governance. 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Ancient civilizations free essay sample

Ancient China was a country that was impacted by its geographic features. Ancient China was a very large country. China’s physical features were very greatly impacted by the contact of other cultures. Some of ancient China’s physical features that prevented them from having contact with other cultures were its large mountains and deserts. This had a good and a bad side to it. The good side was that China was well protected from intruders. However, the bad side to this was that it was it more difficult for China to have contact with other cultures. (Document 2). This also led to China becoming very ethnocentric. Yu was a very important figure in ancient China. Ancient China was in need for water since it was surrounded by deserts and mountains. The solution Yu had to this problem was that he opened passages for the streams throughout the provinces and deepened the existing channels and canals as well as directing them to the streams (Document 4). We will write a custom essay sample on Ancient civilizations or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Mesopotamia was also a civilization that was impacted by its geographic features. The Fertile Crescent was a main part of the Mesopotamian society. It helped with the development of the Mesopotamian society because the crops farmed in the Fertile Crescent could be traded with other countries for goods that the Mesopotamians could not provide for themselves. The Fertile Crescent was the reason that civilizations arose in Mesopotamia. This occurred because it opened up more transportation options and it also improved trading. (Document 5). Ancient Egypt was a third example of a civilization that was affected by their geographic features. Ancient Egypt had periods of time called the â€Å"Old Stone Age, the Middle Stone Age, and the New Stone Age.† These time periods were when civilizations first started to rise. People learned how to make different tools and weapons for everyday use. For example, in the Stone Age, animals affected many people and how they lived. One way in which animals affected the way people lived in the Stone Age was that they would use animal skins and furs for clothing. This also helped to keep the people warm. (Document 1). Another example that shows how Egypt was greatly  affected by its geographic features is that the Nile River was a very important part in the Ancient Egyptian civilization. It played a big part in the development of Egypt because when the Nile flooded all of the crops and gardens would get fertilized and this would help bring food to the people of Egypt. This then helped the Egyptians become great merchants because they would sell those crops for profit in a relatively short time. The Nile River was a major part in helping Ancient Egypt become powerful at trading, farming, and transportation. (Document 6). Therefore, the development of early civilizations was greatly affected by their geographic features. To this day we still use some achievements that these ancient cultures invented. Geographic features play a very important role in civilizations.

Employment Relations HRM in a Workplace

Civil Action Plan Paper Teen Drinking †Health Essay

Civil Action Plan Paper Teen Drinking – Health Essay Free Online Research Papers Hi, my name is Marshall Mathers, I’m an alcoholic†-eminem, â€Å"I sip a Heiniken brew, for my deceased crew†- Nas. These are just two of thousands of quotes in songs referring to alcohol. This can be very influential towards teens who listen to this music to drink at a young age. But then again, what does not? Alcohol is in movies, songs, advertisemnts, pictures, tv shows, and at home used by parents, or other teens. So, with all of these influences, why do 75% of parents believe that their teen does not drink, when over 80% of high school students have at least once had alcohol? Also, why has the government not stepped in to specifically help out teen drinkers through AA type meetings? There are also no non-profit orgainizations geared specifically towards teen drinkers. The most common and perhaps only influential anti-teen drinking addressing would be a brief lesson in heath class. This is not enough. This then leads to many problems, and my groups civil action plan. Parents, and even the government, seem to be ignorant to the fact that children are drinking which is why my group had come up with a support group for teen drinkers. It is first best to hear the teen drinking statitics before anything. Beware, because these first few facts are shocking. The average age for boys to first try alcohol is 11, and is 13 for girls. The average age at which Americans begin drinking regularly is 16 years old. 60% of high-schoolers drink weekly. 11% of alcohol that is consumed by America is consumed by teenagers. Drinking such large amounts at such young ages can lead to serious problem; both mentally and physically. Teenagers, as everybody knows, can be and are very irresponsible. They think not of the consequences, because they only think of the short term benfits. This is why teens are three times more likely to drive drunk then adults. One leading cause of this is because a designated driver, better know as DD, is never established before hand. When that 12:00 am call from the house arrives, by this point, the een and his friends are all unablke to drive. The most important thing to the teen is making it home on time without getting in truoble; not about driving drunk or making it home ALIVE. This is why in our teen drinking anonymous program a DD will be a big topic. The three leading causes of death for 15- to 24-year-olds are automobile crashes, homicides and suicides alcohol is a leading factor in all three. If teens see the consequenes of drining impaired and the importance of a DD, lives will be saved. It is a proven fact that children that have been informed about alcohol and warned of the dangers by their parents are less likely to drink. This will be another part of our civil action plan. Informing parents to tell their children is very crutial. Sending out fliers to homes stating things such as how many American teens/ high school students drink, how many are in drunk driving accidents, and the statistical benefit of teaching your child, young or old, the harms of drinking will have a great impact.if parents preach at home their dissatisfaction of underaged drinker will make young children less likely to drink, and make already drinking teens think twice about what they are doing. Behavioral and drug problems also come hand in hand with teen drinking. Teens age 12 to 17 who use alcohol are more likely to report behavioral problems, especially aggressive, delinquent and criminal behaviors, according to findings of a new study released by the Substance Abuse and Mental Health Services Administration (SAMHSA). The study further revealed that teen alcohol users wether they are heavy or light drinkers report they are more likely to use illicit drugs than non-drinkers. Teens who were current heavy drinkers were 16 times more likely than non-drinkers to have used an illicit drug in the past month. Light drinkers were eight times more likely to have used an illicit drug in the past month than non-drinking adolescents. This is another big problem with take drinking. Many people believe that marijiuana is a gateway drug; once one uses weed enough times theyb want to move on to more â€Å"hardcore† drugs to get a better ad more lasting high, or just for fun. Th is concept can then be applied to alcohol. If alcohol, as it is statistically shown, is in a way a stepping stone to use gateway drugs such a marijiuana, why is alcohol not taken as seriously for teens as marijiuana? The CAP orgainzed group, Teenage Drinker Anonymous or TDA, will show the connection between drugs and alcohol. The task of the Civil Action Plan is to develop solution to a particular issue, and the issue had to be a social issue. Teens who drink are a group in society who suffer from an injustice, because they are unaware of the facts and consequences of drinking. The expert briefly interviwed, Peter Rupert, volunteers a few times a month to work at AA meetings. He agrees that alcohol should be talked about in homes at a young age to prevent teen drinking. He also stated that teens who drink are a group of people who â€Å"suffer from a lack of knowledge†. Setting up the TDA groups will be open to both drinkers, and non-drinkers who would jut like to hear the facts. Fliers will be sent out at school and to homes regarding the amount of teens statistically drinking and what can lead from teen drinking. The fliers and posters will raise a physical awareness. The meetings will be very welcoming and non-judgemental. Hopefully with the TDA orgainization and all the fliers and post ers, awareness of this social injustice will be raised. Research Papers on Civil Action Plan Paper Teen Drinking - Health EssayPersonal Experience with Teen PregnancyEffects of Television Violence on ChildrenHip-Hop is ArtHonest Iagos Truth through DeceptionThe Relationship Between Delinquency and Drug UseStandardized TestingThe Effects of Illegal ImmigrationHarry Potter and the Deathly Hallows EssayComparison: Letter from Birmingham and CritoWhere Wild and West Meet

Film Nior Essay Example | Topics and Well Written Essays - 1250 words

Film Nior - Essay Example Phyllis Dietrichson seduced Walter into killing her husband so that she could benefit from his insurance policy and this made him trick the husband into signing the policy that insured his life for $50,000. Walter accused her of trying to get him to kill her husband and refused but Phyllis convinced Walter how abusive her husband was thus making him agree to kill Dietrichson so that the amount could be doubled due to a fatal accident on a train (Wilder Film). When Dietrichson took the train to attend a college reunion, Walter killed him and posed as him before jumping off the train and placing the body on the tracks making it look like he had fallen off the train to his death. Walter's supervisor was suspicious of Dietrichson's death and further suspected that the wife must have organized the killing. Dietrichson's daughter also told Walter that she believes Phyllis murdered her mother in order to marry her father making him suspect that Phyllis has left him for her lover, Nino Zache tte. The crime falls apart because of the two characters’ absolute mistrust of one another prompting Walter to shoot Phyllis dead and drive to the insurance office to record his confession (Wilder Film). Brick Brick film was produced in 2005 and was written and directed by Rian Johnson that embodies a lot of visual traits of classic film noir and has a very dark plot. Rian was inspired by the hardboiled detective novels written by Dashiell Hammett, and set out to create a unique detective film like the Film Noirs prompting him to choose a contemporary Neo Noir in High School. Brendan Frye who broke up with his girlfriend Emily received a phone call from Emily asking him to assist her since she was in trouble. Emily mentioned some names such as "brick", "poor Frisco", "tug", and "the Pin" that Brendan did not know much about particularly after Emily abruptly and fearfully hanged up the phone conversation. As part of investigation, Brendan arranged to meet Emily at Dode’ s place but Emily refused to talk about the matter thus leaving Brendan in much suspense. Nevertheless, Brendan managed to secretly acquire a hint from Emily’s notepad when he was embracing her and this became very useful in his investigation particularly after she found Emily’s dead body (Rian Film). Brendan discovered that the names mentioned by Emily over the phone conversation were drug barons whom Emily was associated with and even asked the Pin to consider him for a spot in his operation when Laura told Brendan that The Pin had rejected Emily's attempt to join the group. According to Laura, refusal to admit Emily in the drug dealers’ group prompted her to steal the title's brick. As much as Laura offered to help Brendan in carrying out the investigation, he does not trust her especially after he sleeps with her and notices that she must be part of the group which he suspects to have murdered Emily. The fight between r Tug and The Pin, which caused the Pinà ¢â‚¬â„¢s death made Brendan to run away from the police and passes the trunk of Tug's car, where he had hidden the body to ensure that police pin Emily’s murder on Tug. Interestingly, Brendan was very much aware that Laura was a culprit he was looking for and he later went ahead to set Laura to the school administration and accused her of Emily’s murder (Rian Film). Self-Deception The two movies greatly show the aspect of self-deception in many ways living some one wonder whether

Outsourcing Policies On German Car Manufacturing Industry Research Paper

Outsourcing Policies On German Car Manufacturing Industry - Research Paper Example German car manufacturers achieve cost-cutting through sub-contracting and outsourcing. How the process of outsourcing affected the German car industry, how it is done specifically, the related laws on outsourcing and labor and the impact of the recent crisis on the process of outsourcing and sub-contracting are the questions that this paper wishes to answer. With the aid of information coming from company reports, datamonitor, newspapers, websites, and researches, we try to examine all these aspects of outsourcing in the German car manufacturing industry. Business Process Outsourcing is one of the latest trends in business. To outsource is defined in the Merriam-Webster online dictionary as "to procure (as some goods or services needed by a business or organization) under contract with an outside supplier" (Merriam-Webster Incorporated, 2010). This is applied in either the manufacturing stage, the marketing stage or after-sales stage. Germany, specifically the automobile industry is one of those that adopt business process outsourcing as part of the business. The paper will include a detailed study and description of the use of outsourcing practices (to include outsourcing in areas such as components manufacture, servicing and retail operations) in the automotive industry in Germany. Before going into details about different outsourcing practices, I will present a brief overview of supply chain of automotive industry which is crucial to understand in order to fully apprehend the benefits and limitations of outsourcing. Consequently, I will analyze major car manufacturers in Germany in terms of their outsourcing activities and processes. Specifically I intend to focus on three major car producers: BMW, Daimler and VW. Their websites contain detailed annual reports that include also information relevant to outsourcing. In addition, I found substantial amount of information in Datamonitor database about specific outsourcing practices of each car manufacturer as well as trends, competitive landscape and supply chain analysis for global autom otive industry, specific countries, particularly Germany. A necessary part of the paper is an investigation of the effect of outsourcing policies on German car manufacturing companies in the past and in the present. The comparison between the past and the present will be to ascertain the effect of financial crisis and how it has changed the policies and practices of the car manufacturing companies regarding their outsourcing policies. The Research Questions and Objectives Research Questions To formulate