International Association of Bloodstain Pattern Analysts Essay Example for Free

International Association of Bloodstain Pattern Analysts Essay Bloodstain pattern analysis is one technique of several in the discipline of forensic science. This technique of using bloodstains as evidences is not new; however, the application of modern science has made bloodstain analysis more and more reliable (Wikipedia). When current technologies and advances within DNA analysis become available to enforcement agencies, the apprehension of criminals and offenders become less problematic (Wikipedia). The forensic science of bloodstain pattern analysis applies scientific knowledge from other disciplines in order to solve a myriad of practical problems. Bloodstain pattern analysis can draw on biology, chemistry, math, and physics, among others (Wikipedia). When an analyst follows a strict scientific process, this applied science can produce strong, solid evidence (Wikipedia). This is an imperative tool when in the hands of law enforcement. An understanding of bloodstain analysis may allow first responders to a crime scene the know-how in currently collecting and preserving any bloodstain data (Wikipedia). Bloodstain analysts receive specialized training. The foundation course in bloodstain pattern analysis is the Basic Bloodstain Pattern Analysis Course. This is taught at many government and private institutions. The course criterion was developed by the International Association of Bloodstain Pattern Analysts (IABPA) with the following stated purpose: A course of instruction designed for investigators, crime scene technicians, forensic technicians, and others involved in criminal and medical-legal investigations and crime scene analysis. The course is intended to develop a fundamental knowledge of the discipline of bloodstain pattern analysis. The course should illustrate to the student basic principals of bloodstain pattern analysis and the practical application of the discipline to actual casework. The course syllabus is not intended to create an â€Å"instant† expert. There are three classifications of bloodstains: passive, projected, and transfer/contact. These classifications were developed by the IABPA. Passive stains are developed when the acting force creating it is gravity. A passive pattern is then divided into three sub-categories: passive drop, drip pattern, and flow pattern (IABPA). Passive drops are created by the force of gravity alone, and the drip pattern is created when blood drips into blood. The flow pattern is a change in shape or direction due to influence of gravity or movement of the object (IABPA). Projected blood patterns are the result of an energy source being transferred through blood. There are several types: low velocity impact spatter (LVIS), medium velocity impact spatter (MVIS), high velocity impact spatter (HVIS), and expiratory blood (IABPA). The three types of velocity impact patterns are caused when an impact at either a low, medium, or high velocity make contact with the blood source (i. e. medium impact = a battery; high impact = a gunshot). An expiratory pattern is blown out of the nose, mouth, or a wound as a result of air pressure and/or air flow which is the propelling force (IABPA). A transfer/contact stain is the result of a blood bearing object coming in contact with a non-blood bearing object – thus causing the transfer of blood. Two types of transfer/contact patterns are the wipe and swipe pattern. A wipe bloodstain pattern created when an object moves through an existing stain, removing and/or altering its appearance. A swipe pattern is the transfer of blood from a moving source onto an unstained surface (IABPA). Blood splatter flight characteristics show that blood tends to form a sphere in flight opposed to the artistic teardrop shape. This is the result in the surface tension that binds the molecules together. This spherical shape is important to the calculation angle of incidence of blood when it hits a surface. This angle is then used to determine the point of origin (PO) – the original area where the blood originated in (Wikipedia). In 1954, Marilyn Sheppard was bludgeoned to death in her home. Her husband, Dr. Sam Sheppard survived what he called an attack by an intruder. Dr. Sheppard reported that he had been knocked unconscious as he tried to defend his wife (Lyle). Their home was ransacked. Investigators would come to realize that Dr. Sheppard had no blood located on his body nor clothing, and he denied ever cleaning up before the police arrived (Lyle). This troubled the police. The attack was so brutal that the killer would have been covered in blood, and Dr. Shepard should have had blood transfers located on his body or clothes. Sheppard had no blood located on his hands, which would be impossible because he said he checked for a pulse of his wife’s neck, which was covered in blood. Furthermore, Sheppard claimed that his watch, wallet, ring and keys were missing. This was true. A bag with these items was found no too far from the house; however, they had to traces of blood. Moreover, Sheppard’s pants had no blood on them – impossible is the killer robbed him with bloody hands (Lyle). The watch, however, did have traces of blood. Theses blood splatters came from flying droplets, indicating that the watch must have been close when the victim was received the fatal blows. If the watch made contact with her neck – as he checked for a pulse – the watch would have blood smears and not droplets (Lyle). Police determined that Dr. Sheppard most likely bludgeoned his wife to death. Then he cleaned himself and trashed the items outside the house were police would find them and made the house look as if it was a burglary (Lyle). Based in large part on the blood evidence, or lack of it, Sheppard was convicted of murder. After spending ten years in prison, Sheppard was released when the U. S. Supreme Court overturned his conviction. A representative from the coroner’s office stated that the blood located on Sheppard’s watch represented a blood splatter. This means the watch must have present when the blows were struck (Lyle). A renowned criminalist, Dr. Paul Kirk testified that the blood on the watch was a result of Sheppard checking his wife’s pulse. If so, why was the watch found outside the house? This controversy still surrounds the case. In 2004, Nick Berg was horrifically murdered by insurgents in Iraq. His throat was cut and he was decapitated. His body was found by an Iraqi overpass. The tape was on review on May 11, 2004 for a type of bloodstain analysis. Laura Mansfield, certified in bloodstain analysis by the Laboratory of Forensic Science and is a member of the IABPA, begins her analysis of the footage (Crime Library). It’s reported: â€Å"The time displays 13:45:47 in the lower right corner, the victim is pushed onto his left side where his legs are bent at the knees and raised toward his chest and his arms still tied behind his back. At this point, the video becomes out of focus and essentially useless for the purposes of analysis from approximately 90 frames. As the video comes back into focus, the primary assailant is viewed using the knife to cut the throat of the victim, beginning at the area near his left carotid artery. Almost immediately, blood is seen pouring onto the floor (target surface) from the wound caused by the incision (Crime Library). † There appears to be an edit point. At this point the primary insurgent is no longer holding the knife. â€Å"The individual wearing the white hood and previously standing on the right side of the primary assailant is now using the knife in a saw-like manner, holding the knife in (his) right hand while holding the victims hair with (his) left hand. At 13:47:xx, the individual wearing the white hood ultimately detaches the victims head from his body and holds the head outward in (his) left hand, still holding the knife in (his) right (Crime Library). † The frames that follow appear to jump, at which time the victim’s head is completely detached and the primary object in the frame. Through out the video, time changes frequently from military time back to â€Å"regular† time and vice versa. â€Å"Interestingly, the time display on the video changes to 2:46:20 (regular time format) and then switches back to 13:48:45 (military format) while the victims head is shown detached from his body in a similar series of frames (Crime Library). † Bloodstain pattern analysis is an age-old technique, which with new technologies and advancements aid in the capture and prosecution of criminals. This analysis procedure is used in many different ways and draw upon a myriad of disciplines. In result of a strict process, bloodstain pattern analysis will prove solid, concrete evidence and is a useful tool in the hands of law enforcement. References IABPA (International Association of Bloodstain Pattern Analysts). Suggested IABPA Terminology List. Date visited 8 April 2006. http://www. iabpa. org/Terminology. pdf Lyle, D. P. , MD. Uncovering the Evidence: Those Messy Bloodstains. Forensics for Dummies. John Wiley Sons Inc. p. 98 Nick Berg Tape. Crime Library. Court Tv. Date visited 8 April 2006. http://www. crimelibrary. com/about/authors/mansfield/ Wikipedia Online. Bloodstain Pattern Analysis. Date visited 9 April 2006. http://en. wikipedia. org/wiki/Bloodstain_pattern_analysis

A Review on an Article: If the European Economy Is So Shaky, Why Is the

The article on the Economist, â€Å"If the European economy is so shaky, why is the euro so strong?† by R.A is explaining why and how the value of euro is still remaining strong, even though the economy of Europe is going through many struggles. Throughout the article, it is discussed how appreciation of a currency may not always be good improvement and what negative consequences the appreciation of a currency can lead to. The article also states how the moves of the exchange rates cannot easily be explained and goes into further details about the euro exchange rates. The article starts by stating that recently the euro zone has been facing a good trend of improvement in terms of economy and managed to pull out of the recession. In the euro zone, the unemployment is decreasing and worries regarding the crises are disappearing by the time. However, there is the fear of deflation. As the article continues, it explains how appreciation of a currency can cause problems that are very significant and serious. In order to better explain this point, an example of the US cars is given in the article; if US dollar appreciates compared to euro or yen while the price of the cars do not vary, it will be more expensive for the countries that uses euro or yen as their currencies to purchase US cars. As a result of this appreciation in the value of dollars, the number of cars exported will decrease in the United States. This is exactly the same reason why Europe has a fear for a strong currency; the strong euro currency makes European goods and services more expensive to other nations and thus, lowers the amount sold abroad. Also, since the households, firms and government is cutting back, the development and growth of the economy is highly dep... ...s products and services in demand throughout the globe, hence the euro's strength, at least as determined by the "demand" side of the equation. The "supply" side of the equation would involve to what degree the European Central Bank is pushing credit expansion, which tends to push the value of the euro downwards. In addition to this, the article uses some expressions that does not sound very right when thinking about a big economy as Europe; for example, it is mentioned in the end of the article that, â€Å"The surest way to bring it down is to make more euros†. European system certainly has a slow, hardly predictable response time, many variables, and its behavior is definitely nonlinear. Thus, using such a simple and straight forward expression regarding the exchange rate of euros may not be very right thing to do, even though it is a correct statement to some extent. A Review on an Article: If the European Economy Is So Shaky, Why Is the The article on the Economist, â€Å"If the European economy is so shaky, why is the euro so strong?† by R.A is explaining why and how the value of euro is still remaining strong, even though the economy of Europe is going through many struggles. Throughout the article, it is discussed how appreciation of a currency may not always be good improvement and what negative consequences the appreciation of a currency can lead to. The article also states how the moves of the exchange rates cannot easily be explained and goes into further details about the euro exchange rates. The article starts by stating that recently the euro zone has been facing a good trend of improvement in terms of economy and managed to pull out of the recession. In the euro zone, the unemployment is decreasing and worries regarding the crises are disappearing by the time. However, there is the fear of deflation. As the article continues, it explains how appreciation of a currency can cause problems that are very significant and serious. In order to better explain this point, an example of the US cars is given in the article; if US dollar appreciates compared to euro or yen while the price of the cars do not vary, it will be more expensive for the countries that uses euro or yen as their currencies to purchase US cars. As a result of this appreciation in the value of dollars, the number of cars exported will decrease in the United States. This is exactly the same reason why Europe has a fear for a strong currency; the strong euro currency makes European goods and services more expensive to other nations and thus, lowers the amount sold abroad. Also, since the households, firms and government is cutting back, the development and growth of the economy is highly dep... ...s products and services in demand throughout the globe, hence the euro's strength, at least as determined by the "demand" side of the equation. The "supply" side of the equation would involve to what degree the European Central Bank is pushing credit expansion, which tends to push the value of the euro downwards. In addition to this, the article uses some expressions that does not sound very right when thinking about a big economy as Europe; for example, it is mentioned in the end of the article that, â€Å"The surest way to bring it down is to make more euros†. European system certainly has a slow, hardly predictable response time, many variables, and its behavior is definitely nonlinear. Thus, using such a simple and straight forward expression regarding the exchange rate of euros may not be very right thing to do, even though it is a correct statement to some extent.

Canadian Culture Essay

Canada is located in the northern portion of the continent of North America, extending, in general, from the 49th parallel northward to the islands of the Arctic Ocean. Its eastern and western boundaries are the Atlantic and Pacific Oceans respectively. Its land area totals 3,851,809 square miles (9,976,185 square kilometers). The easternmost portion of the country is a riverine and maritime environment, consisting of the provinces of Newfoundland, Labrador, Nova Scotia, Prince Edward Island, and New Brunswick. The central portion of the country, in its southern areas, is primarily boreal forest (the provinces of Ontario and Quebec). This forest region extends across the entire country from the eastern slopes of the Rocky Mountains through to the Atlantic coast, and is dominated by coniferous trees. These variations have had important social and cultural effects. The largest segment of the population resides in the central Carolinian region, which has the richest and most varied agricultural land and, because the Great Lakes waterway system dominates the central portion of the country, is also where most of the major manufacturing is located. The savanna or prairie region is more sparsely populated, with several large urban centers in a network across the region, which is dominated by grain farming, cattle and other livestock production, and more recently, oil and natural gas extraction. The two coastal regions, which have some agricultural production, are best characterized by the dominance of port cities through which import and export goods move. In the northern section of the center of the country, also sparsely populated, resource extraction of minerals and lumber, has predominated. The effect of this concentration of the population, employment, and productive power in the central region of the country has been the concentration of political power in this region, as well as the development over time of intense regional rivalries and disparities in quality of life. Equally important, as employment in the center came to dominate gross national production, immigration has tended to flow into the center. This has created a diverse cultural mix in the central region of the country, while the prairie and the eastern maritime region have stabilized ethnically and culturally. The consequence of these diverse geographies has been the development of a rhetoric of regional cultures: Prairie, Maritime, Central, and because of its special isolation, West Coast. A final differentiation is between urban and rural. Local cultural identity is often marked by expressions of contrasting values in which rural residents characterize themselves as harder working, more honest, and more deeply committed to community cooperation, in contrast to urban dwellers [pic] Canada who are characterized by rural residents as greedy, dishonest, arrogant, and self-interested. Urban dwellers express their own identities as more modern and forward looking, more sophisticated, and more liberal in their overall social values, and perceive rural residents as conservative, overdependent on outmoded traditions, unsophisticated, and simple minded. This distinction is most explicit in Quebec, but also plays a key role in political, social, and cultural contentions in Ontario. Demography . The official population at the last census calculation, in 1996, was 29,672,000, an increase over the previous census in 1991 of about 6 percent in five years. The previous five-year increase was almost 7 percent. There has been a slowing population increase in Canada over the last several decades, fueled in part by a decline in the crude birthrate. This slowing of growth has been offset somewhat by an increase in immigration over the last two decades of the twentieth century, coupled with a slowing of emigration. Statistics Canada, the government Census management organization, is projecting a population increase of as much as 8 percent between 2001 and 2005, mostly through increased immigration. Language Canada is bilingual, with English and French as the official languages. English takes precedence in statutory proceedings outside of Quebec, with English versions of all statutes serving as the final arbiter in disputes over interpretation. As of 1996, the proportion of Canadians reporting English as their mother tongue was just under 60 percent while those reporting French as their mother tongue was slightly less than 24 percent. The percentage of native English speakers had risen over the previous decade, while that of French speakers had declined. At the same time, about 17 percent of all Canadians could speak both official languages, though this is a regionalized phenomenon. In those provinces with the largest number of native French speakers (Quebec and New Brunswick), 38 percent and 33 percent respectively were bilingual, numbers that had been increasing steadily over the previous twenty years. In contrast, Ontario, which accounts for more than 30 percent of the total population of Canada, had an English-French bilingualism rate of about 12 percent. This is in part a result of the immigration patterns over time, which sees the majority of all immigrants gravitating to Ontario, and in part because all official and commercial services in Ontario are conducted in English, even though French is available by law, if not by practice. English-French bilingualism is less important in the everyday lives of those living outside of Quebec and New Brunswick. First Nations language groups make up a significant, if small, portion of the nonofficial bilingual speakers in Canada, a fact with political and cultural importance as First Nations groups assert greater and more compelling claims on political and cultural sovereignty. The three largest First Nations languages in 1996 were Cree, Inuktitut, and Ojibway, though incomplete census data on First Nations peoples continues to plague assessments of the extent and importance of these mother tongues. Immigration and cultures Changing immigration patterns following World War II affected linguistic affiliation. In the period, from 1961 to 1970, for example, only 54 percent of immigrants had a nonofficial language as mother tongue, with more than two-thirds of this group born in Europe. Almost a quarter of them reported Italian, German, or Greek as mother tongue. In contrast, 80 percent of the 1,039,000 immigrants who came to Canada between 1991 and 1996 reported a nonofficial language as mother tongue, with over half from Asia and the Middle East. Chinese was the mother tongue of just under 25 percent, while Arabic, Punjabi, Tagalog, Tamil, and Persian together accounted for about 20 percent. In 1971, the three largest nonofficial mother tongue groups were German, Italian, and Ukrainian, reflecting patterns of non-English and non-French immigration that have remained relatively constant through most of the twentieth century. In the period ending in 1996, this had changed, with the rank order shifting to Chinese, Italian, and German. This is reflected in regional concentrations, with Italians concentrated heavily in Ontario, Germans in both Ontario and the Prairie regions, and Chinese and other Asians most heavily represented in southern Ontario and in British Columbia. A gradual decline in out-migration from Europe, coupled with political changes in China and throughout Asia, leading to increased out-migration from these areas, is changing the ethnic and linguistic makeup of Canada. It should be stressed, however, that these changes are concentrated in two or three key urban centers, while linguistic affiliation elsewhere in the country remains stable. This is likely to change in the early twenty-first century as an aging cohort of European immigrants declines and out-migration from Europe continues to decrease. These shifts will come to have increasingly important cultural effects as immigrants from Asia and, most recently, from certain areas throughout the continent of Africa, come to influence the political and social life of the core urban centers in which they settle. Symbolism. This is an area of considerable dispute in Canada, in large part because of the country’s longstanding history of biculturalism (English and French) and perhaps most importantly because of its proximity to the United States, whose symbolic and rhetorical influence is both unavoidable and openly resisted. Ethnic and cultural diversity in Canada, in which different cultural groups were expected to maintain their distinctiveness rather than subsume it to some larger national culture, which is the historical effect of the English-French biculturalism built into the Canadian confederation, means that national symbols in Canada tend to be either somewhat superficial or regionalized. There are, however, certain symbols that are deployed at both official and unofficial events and functions which are generally shared across the entire country, and can be seen as general cultural symbols, even if their uses may not always be serious. The core values that inform these symbols are cooperation, industriousness, and patience—that is, a kind of national politeness. The Canadian symbolic order is dominated by a concern for order and stability, which marks Canadian identity as something communal rather than individualistic. Canada throughout its history might best be described as a nation of nations. Two European colonial powers dominate the history of Canada and its emergence as a nation: France and Great Britain. In time Britain emerged as the dominant political and cultural force in Canada, but that emergence exemplifies the sense of compromise and cooperation on which Canadian social identity is founded. While Britain, and later English Canada, came to be and remain the most powerful part of the Canadian cultural landscape, this dominance and power exists in a system of joint cultural identity, with French Canada, in Quebec and in other parts of eastern Canada, remaining a singular and distinctive cultural entity in its own right. This complex antagonism, which has been a thread throughout Canada’s emergence as a nation, has also led to a particular kind of nation. Most important, the development of the Canadian nation, however uneven the power of the English and the French, has been characterized by discussion, planning, and compromise. The gradual opening of all of Canada to European control, and its coming together in 1867 as a national entity, was not the result of war or revolution but instead, of negotiation and reconciliation. It was an orderly transition managed almost like a business venture, through which Canada obtained a degree of sovereignty and Great Britain continued to hold Canada’s allegiance as a member of the British Empire. When, in the early 1980s Canada would take the final step towards political independence by adopting its own constitution, it would do so through negotiation as well, and again, the antagonism between English and French Canada, which resulted in the Government of Quebec refusing to sign the constitutional enabling agreement would provide both the drama of the moment, and its fundamental character, one of compromise and collaboration. Leading up to and following the emergence of Canada as an independent political state in 1867, English Canada and English identity dominated the political and cultural landscape. The remaining French presence, in Quebec and throughout the eastern part of the country, while a strong cultural entity in itself, exercised only limited influence and effect at the national level. English symbols, the English language, and the values of loyalty to the English crown prevailed throughout the nation as the core underpinnings of national identity. The dominance of English Canada in terms of national identity, especially in a federal system in which binationalism and biculturalism were enshrined in the founding legislation of the country, exercised a powerful effect on ethnic relations, but that effect was not ethnic homogenization. Instead, the dominance of English Canada served as a major locus of ongoing tension between the two national identities of Canada, a tension which, in he period from the 1960s onward, has come to be expressed in growing French-Canadian nationalism and so far unsuccessful attempts on the part of French Canada to secede from the Canadian confederation. This tension—which is built into the principles of the confederation itself, which recognizes the duality of Canadian national identity— while regularly threatening the unity of the federation, has also had a mollifying effect on ethnic divisions more generally. The main exception to this has been the relationship between the dominant Fren ch-English state and aboriginal peoples. Colonial relations with indigenous ethnic groups worldwide have often been marked by violent conquest. While violence did play a role in these relationships in Canada, more often than not aboriginal peoples simply had their ethnic and cultural identities erased. The use of forced schooling, including the removal of children from their families, for example, sought to annul aboriginal cultural identities Food in Daily Life . The agricultural and ethnic richness of Canada has led to two distinctive characteristics of everyday food consumption. The first is its scale. Canadians are â€Å"big eaters,† with meat portions in particular dominating the Canadian meal. There are generally three regular meals in a given day. Breakfast, often large and important in rural areas, but less so in urban areas, is most often not eaten in a group. Lunch, at midday, is most often a snack in urban areas, but remains a substantial meal in rural centers. Dinner, the final formal meal of the day, is also the meal most likely to be eaten by a residential group as a whole, and it is the largest and the most socially important meal of the day. It is the meal most often used as a social event or to which invitations to nonfamily members are extended, in contrast with lunch which is often, for adults, shared with coworkers. Meat plays a key role in all three of the formal meals, but with increasing importance at breakfast and dinner. Dinner should have some special, and most often, large, meat portion as its key component. Each of these three meals can be, and often are, very substantial. There are general rules concerning appropriate foods for each meal, rules that can be quite complex. For example, pork can figure in each meal, but only particular kinds of pork would be considered appropriate. Pork at breakfast may appear as bacon, or sausage, in small portions. Both of these products are made with the least valuable portion of the pig. At lunch, pork may appear in a sandwich in the form of processed meats, also made from the least valuable portion of the pig. For dinner, pork appears in large and more highly valued forms, such as roasts or hams, which require often elaborate preparation and which are presented to diners in a way that highlights their value and size. The other main feature of Canadian food is diversity. The complex ethnic landscape of Canada and the tendency of ethnic groups to retain a dual cultural orientation have meant that Canadian cuisine is quite diverse in its content, with many ethnic dishes seen as somehow quintessentially Canadian as well. Whether pizza or chow mein, cabbage rolls or plum pudding, Canadian cuisine is best characterized as eclectic rather than consistent in content. There are a small number of food items that are considered distinctively Canadian, such as maple syrup, but overall the Canadian diet is drawn from a panoply of ethnic sources. Food Customs at Ceremonial Occasions. Ceremonial food does not generally differ greatly in content from everyday foods. What distinguishes food in ceremonial settings, such as state dinners, is not the type of food but the amount of food served and the complexity of its presentation and consumption. Ceremonial dinners are often made up of a long list of dishes served in a rigid sequence, eaten with utensils specified for each portion, and presented in often elaborate arrangement either generally, on the table as a whole, or in the particular portions placed on each diner’s plate. The same general consideration applies to meals for more private special occasions, such as those marking important religious holidays such as Christmas. The number of discrete dishes is usually quite large, the preparation of each is often specialized and involved, and portions consumed are more often than not greater than what one would consume under other circumstances. These more private special occasion meals often involve entire extended families sharing in both preparing and eating the meal. There is another special meal worth mentioning, the potluck. Potluck† is derived from the word potlatch, a special occasion of many West Coast First Nations peoples. The potluck involves each guest preparing and bringing a dish to the event, to be shared by all the diners. The key component of this particular kind of meal is food sharing among friends as opposed to food making for family. In general, potluck meals are meals shared by friends or coworkers. They express the symbolic im portance of the meal as a part of the moral geography of social relations among nonkin, but distinguish this meal as an act of food sharing rather than an act of food preparation. That is, the potluck meal expresses a sense of community and kindness, while the family meal expresses a sense of service, duty, and family solidarity. Basic Economy. Canada is a resource rich, but land and people poor, country. While physically vast, there are geographic limitations on where people can live such that most of the population is located around the Great Lakes, and in the Saint Lawrence River Valley. This has meant, however, that the natural resources throughout the country can be exploited more fully. Key to Canada’s basic economy is its role as a resource base, not only for its own manufacturing, but for export as well. Minerals and ore, forestry products, and in particular in the twentieth century, oil and gas, have been the foundation of the Canadian economy since European conquest of the area. Farming is also key to the Canadian economy, although most of Canada’s agricultural production The single largest area of economic growth in Canada since the 1970s has been in the â€Å"service† sector, the part of the economy which provides services rather than goods for sale. r Trade. Canada exports around the world, but its most important export and import trading partner is the United States. The manufacturing and export of large equipment, and in particular farm equipment, is the second largest component of Canadian manufacturing and trade. At the same time, Canada remains a major resource exporter. In particular, Canada exports raw materials such as petro-chemi cals and oil, minerals and ores, and forestry products. Division of Labor. Labor in Canada is unevenly divided between skilled professional, skilled manufacturing, and general unskilled such as service workers. With increased manufacturing efficiency, the skilled manufacturing labor force has declined in size, though not in economic impact, while the general unskilled labor force has increased; at the same time skilled professionals—whether doctors, computer programmers, and other new economy professionals—has also increased. Access to different jobs is determined in part by education and training and in part by social networks.

Lewis Dot Structure Example - Octet Rule Exception

Lewis dot structures are useful to predict the geometry of a molecule. Sometimes, one of the atoms in the molecule does not follow the octet rule for arranging electron pairs around an atom. This example uses the steps outlined in How to Draw A Lewis Structure to draw a Lewis structure of a molecule where one atom is an exception to the octet rule. Review of Electron Counting The total number of electrons shown in a Lewis structure is the sum of the valence electrons of each atom. Remember: non-valence electrons are not shown. Once the number of valence electrons has been determined, here is the list of steps normally followed to place the dots around the atoms: Connect the atoms by single chemical bonds.The number of electrons to be placed is t-2n, where t is the total number of electrons and n is the number of single bonds. Place these electrons as lone pairs, starting with outer electrons (besides hydrogen) until every outer electrons has 8 electrons. Place lone pairs on most electronegative atoms first.After lone pairs are placed, central atoms may lack an octet. These atoms form a double bond. Move a lone pair to form the second bond.Question:Draw the Lewis structure of the molecule with molecular formula ICl3.Solution:Step 1: Find the total number of valence electrons.Iodine has 7 valence electronsChlorine has 7 valence electronsTotal valence electrons 1 iodine (7) 3 chlorine (3 x 7)Total valence electrons 7 21Total valence electrons 28Step 2: Find the number of electrons needed to make the atoms happyIodine needs 8 valence electronsChlorine needs 8 valence electronsTotal valence electrons to be happy 1 iodine (8) 3 chlorine (3 x 8)Total valence electrons to be happy 8 24Total valence electrons to be happy 32Step 3: Determine the number of bonds in the molecule.number of bonds (Step 2 - Step 1)/2number of bonds (32 - 28)/2number of bonds 4/2number of bonds 2This is how to identify an exception to the octet rule. There are not enough bonds for the number of atoms in molecule. ICl3 should have three bonds to bond the four atoms together. Step 4: Choose a central atom.Halogens are often the outer atoms of a molecule. In this case, all the atoms are halogens. Iodine is the least electronegative of the the two elements. Use iodine as the center atom.Step 5: Draw a skeletal structure.Since we do not have enough bonds to connect all four atoms together, connect the central atom to the other three with three single bonds.Step 6: Place electrons around outside atoms.Complete the octets around the chlorine atoms. Each chlorine should get six electrons to complete their octets.Step 7: Place remaining electrons around the central atom.Place the remaining four electrons around the iodine atom to complete the structure. The completed structure appears at the beginning of the example. Limitations of Lewis Structures Lewis structures first came into use early in the twentieth century when chemical bonding was poorly understood. Electron dot diagrams help illustrate electronic structure of molecules and chemical reactivity. Their use remains popular with chemistry educators introducing the valence-bond model of chemical bonds and they are often used in organic chemistry, where the valence-bond model is largely appropriate. However, in the fields of inorganic chemistry and organometallic chemistry, delocalized molecular orbitals are common and Lewis structures dont accurately predict behavior. While its possible to draw a Lewis structure for a molecule known empirically to contain unpaired electrons, use of such structures leads to errors in estimating bond length, magnetic properties, and aromaticity. Examples of these molecules include molecular oxygen (O2), nitric oxide (NO), and chlorine dioxide (ClO2). While Lewis structures have some value, the reader is advised valence bond theory and molecular orbital theory do a better job describing the behavior of valence shell electrons. Sources Lever, A. B. P. (1972). Lewis Structures and the Octet Rule. An automatic procedure for writing canonical forms. J. Chem. Educ. 49 (12): 819.  doi:10.1021/ed049p819Lewis, G. N. (1916). The Atom and the Molecule. J. Am. Chem. Soc. 38 (4): 762–85. doi:10.1021/ja02261a002Miessler, G.L.; Tarr, D.A. (2003). Inorganic Chemistry (2nd ed.). Pearson Prentice–Hall. ISBN 0-13-035471-6.Zumdahl, S. (2005). Chemical Principles. Houghton-Mifflin. ISBN 0-618-37206-7.