Assignment #2: Personal Ethical Philosophy Statement
All leaders need some type of philosophy to help guide their actions. This assignment is designed to help you clarify the principles that you choose to live by in your life and work. In identifying and defining these principles, your goal is to establish an ethical code that will serve as a moral guide for you when making decisions. When developing your ethical code, keep the following guidelines in mind:
Incorporate what you have learned in the course, what you have reflected on and discussed during the course thus far. (The summary provided at the end of the textbook – Chapter 17 (Ethical Leadership A Primer, 2018, Robert McManus, Stanley Ward, Alexandra Perry) – should help you recall the concepts presented.) This should include:
1) How you believe your ethical code suits your lifestyle, your career, your interaction with others, and your broad role as a human on this planet.
2) How that ethical code is consistent with your evolving sense of your own leadership and the leadership of those with whom you interact in your career.
3) How that ethical code can inform the practical decisions you make in your life and your career.
4) The ways your ethical code is distinctive and how it reflects your unique identity.
Use the language and concepts you have been exposed to in this course to articulate your ideas.
Mechanics: This assignment is to be submitted as an academic essay. You are required to reference the readings and articles that provide evidence of effectiveness for your proposed plan. Give your paper a title, a brief introduction, and a conclusion. Adhere to the American Psychological Association (APA) guidelines for citation and references. Limit it to 1,500-2,500 words (6-10 pages) typed, double-spaced, Times New Roman, 12 point font, 1″ margins.
Information on the American Psychological Association (APA) style guide can be found in the APA style guide located in the CLU library or on the APA Style website. Additional tools are available through the student resources module.
Paper on Ethical leadership
Beauty Miracles With Orange Peel English Literature Essay
Beauty recipes made out of natural ingredients can be extremely fruitful besides they’re certainly harmless and don’t pose any side-effects. For instance, an orange peel mask can give you miraculous results. It will help remove your sun-tan, caused by excessive exposure to the sun’s rays and brighten your skin tone leaving you looking gorgeous and radiant. Here is a quick look on how an orange peel mask can be prepared and used to get a glowing and radiant skin. Ingredients for orange peel mask Orange peel powder and milk or water Preparation Peel the oranges and leave the peels to dry out, naturally, until they become hard. If possible dry them in shade. Take the hard dried peels and grind them into a fine powder. Make a smooth paste with equal amounts of both orange peel powder and milk. You can even replace milk with water instead. Blend it well. Let it stand for an hour or two before applying it. Application Gently spread the mixture all over your face with the help of a brush and leave it for half-an-hour or till it dries completely. Wash your face with cold water. Do not scrub your face as it may cause damage to your skin. Benefits and usefulness of orange peel Orange peel mask is extremely beneficial for those who have oily skin. The incessant oil secretion from the oil glands makes you look greasy and gives birth to unwanted and ugly looking boils and pimples. To prevent this orange peel mask will come in handy. Use this facial mask twice a week for best results. It not only helps absorb the excessive oil but also works wonder in exfoliating dead skin cells. As a result, your skin gets rejuvenated and becomes more radiant and youthful. Other uses of orange peels Orange peel can be used in several ways to enhance your beauty. You can prepare a refreshing bath by using orange peel along with lemon peel. Orange peel is very soothing for the skin while lemon peel acts as an astringent. Put some herbs like chamomile, comfrey leaves with them and soak them all in the water, and leave it like this overnight. After straining, add this liquid to your bathtub filled with hot water and get ready for a rejuvenating experience. Orange peal beauty recipes, homemade orange peel mask, orange peel for skin care Article 2 How to plump up your thinning skin as you get older You may find your skin getting thinner as you get older, not just your face skin but also the skin on your arms and legs. This can certainly cause lack of self confidence, maybe that’s one reason why a lot of people are undergoing surgeries to plump up their thinning skin. This is quite an ordeal which is both risky and expensive. However, there are certain things that people should be aware of regarding their own skin, and these little bits of information can come in handy to maintain and protect the youthfulness of their skin without undergoing a surgeon’s knife. In our bodies, certain tiny things called free radicals float around causing oxidative damage to the body tissues. This causes aging. To keep a check on free radicals, antioxidants are needed. Fruits and vegetables that contain antioxidants should be included in the diet, and that’s the first thing we can all do to prevent ageing. Collagen and elastin are also needed to keep the skin plumped up, which unfortunately our bodies begin to produce less as we age. This problem can be overcome with the usage of anti-aging creams, especially the ones enriched with antioxidants. Focus on antioxidants Add plenty of dark colored fruits and green leafy vegetables in your regular diet in addition to using anti-aging creams. Eating right and eating healthy are the most important things for maintaining a youthful skin. This will cause your body to start producing more collagen and elastin, and the thinning of the skin due to ageing will get delayed significantly. Your skin will look young and radiant and your wrinkles will begin to disappear. Some tips that will help you to plump up your skin Loss of subcutaneous fat and moisture coupled with the damage done by UV rays causes facial lines and wrinkles to appear. With ageing, skin elasticity declines causing the skin to sag. To prevent all this, use need creams enriched with Vitamins A and E that can help increase the moisture content of the skin. Also, this will help in rebuilding of the damaged collagen structure. Also regular exfoliation will give you good result by scrubbing away the thin outer layer containing dead cells. This can help significantly in the reduction of fine lines and ageing spots. Also regular exfoliating promotes the growth of new and healthy skin tissues. Beauty treatment products called ceramides, are highly beneficial in treating fine lines, wrinkles and thinning skin, by nourishing the underlying fatty tissues. Prevent thinning skin, preventing skin ageing, plump-up thin skin, anti ageing cosmetics Article 3 Make your temporary tattoo at home Body art and tattoos have become a great fad among today’s younger generation and most of them want to get them just like their favorite celebrities. However, a lot of them are not ready to commit to permanent tattoos. But temporary tattoos are a great alternative and what’s best is that you can easily make these temporary tattoos at home using clipart or stencils. Instructions on how to make temporary tattoos with clipart First decide on the design of the tattoo, taking into consideration other things like the size, color palette to be used on it and also the place where you want to make the tattoo on your body. Get hold of a temporary tattoo paper, a color printer and a computer system with a desktop publishing program to make a tattoo of your choice. Select any of the clipart designs which you can find in the desktop publishing program, or download one from the net. Numerous clipart graphics are there to help you choose. You can also scan an existing design of your choice. Make sure you choose designs that will look great in the form of a tattoo and are not too intricate or clumsy. Put the chosen clipart or design on a computer program so that you can customize it the way you want. You can determine the size or add some extra colors or to make any further alteration if needed. Once done, print the tattoo design on the temporary tattoo paper. Follow the instructions as directed on the temporary tattoo paper and apply the tattoo carefully. Instructions on how to make temporary tattoos with stencils There are ample of stencil designs easily available in the market and stores, that are stuffed with craft items. Choose designs that reflect your personality and lifestyle. The stencil design can also be hand painted or you can do it yourself but make sure it does not involve too much of detailing. Keep it simple yet prominent, so that the tattoo comes out beautifully. Always clean the area of your body part where the tattoo is to be made properly with soap or some face wash, before making the tattoo. After that, place the stencil design and fill the tattoo with body paints. And let the paints dry fully before you remove the stencil, or else the colors may get smudged. Article 4 Fragrances and smells that arouse men A survey has been conducted by the Chicago’s Research Foundation on fragrances that attract men in the age-group of 18 to 60. Also the detailed study show how men have responded to different fragrances and what was the impact of the smells on their sexual desires. The scents, men have responded favorably to, are mostly fruity and floral fragrances. For instance, the scent produced by lavender blended with pumpkin pie attracts forty percent men. Similarly, orange flavored fragrances mixed with lily of the valley returned a favorable reaction in a lot of men. The smells of sandalwood and vetiver are also had a sexually arousing effect on men. Pumpkin pie merged with the scent of doughnuts also happens to produce significant arousal in lots of men according to the survey. The scientists at Chicago’s Research Foundation have also propounded a theory that there are aphrodisiac qualities present in the pumpkin pie which contain substances like vanilla and cinnamon due to which men feel aroused. Apart from these smells generated from fruits, there are other scents produced from unusual substances like black licorice, popcorn and cola that had an equally invigorating effect on men’s sexual desires. It has been found that 20 percent of men responded well even to strange fragrance combinations like the scent of black licorice mixed with the aroma of cola. There were also a small percentage of men got sexually aroused with the smell of doughnut and cola put together. The smell of popcorn scored no less on this scale. Especially, popcorns braised with flavored butter managed to produce an unusual scent that was a mood lifter for 9 percent of men who were studied during the research. So Ladies, you now know what to put on the dining table to get your man excited sexually. Perfumes that excite men Resin plant contains chemicals that increase or propel natural human body smells. However, the effect of pheromones are not that strong on sexual arousal, both in men and women, as humans are not able-enough to find their partners by tracking human pheromones. Fragrances with resins can be very intense, sensual and seductive. Lancôme Magic Noire, Givenchy L’Interdit, Van Cleef and Arpels Pour Homme are some that attract men dominantly. Fragrances enriched with orange flavor namely Yves Saint Laurent Baby Doll and Tommy Hillfiger Dreaming are also invigorating fragrances, and are perfect to uplift a man’s mood. These perfumes and many others with similar fragrances ignite the deep recesses of the man’s brain. Fragrances men love, smells that excite men, perfumes that arouse men sexually Article 5 How to tighten loose skin after weight loss Loosing weight can definitely help one to look good, but it can have its downsides too, especially when extremely obese people loose weight suddenly. If someone has lost his weight faster than usual or in a very short span of time, that individual is bound to be left with loose hanging skin, mainly around the abdominal region. But there is nothing to worry as this is natural. Follow some simple steps to firm up your skin. Many would like to opt for painful surgeries to tighten the skin, but instead of doing that, be patient and let time do the healing. You can’t expect it to happen overnight. So don’t be fidgety and don’t rush. Skin nourishment is very important to tighten your skin. Make sure you exfoliate the dead skin cells every other day and keep a check on the skin elasticity. Regular skin care routine will help your skin to be get back to normal. Take hot water bath once or twice a week and don’t forget to add some pure sea salt to the bath water. Remember to mix in the salt well into the water, until it gets dissolved. The salt will help remove all the toxins out of your skin and thus tone up your skin. Not just that, your body and muscles will get relaxed and revitalized with this hot water bath. Find out the percentage of your body fat. By doing so, you will be able to figure out the amount of loose skin you are left with after loosing weight. Speaking of skin elasticity which is important for tightening of the skin, you have to increase your body’s production of collagen and elastin and you can achieve it by applying aloe vera extract or yeast extract and consuming soy protein. Once your skin’s natural defense gets strong, your skin will become firm and supple. Skin healthy foods like coconut, cucumber, tomato and olives are excellent for skin tightening. Consuming these on a regular basis will show marked improvement on your skin-elasticity. Supplement your diet with Hyaluronic acid and magnesium, as both these are essential for the collagen and elastin production within the body. Loose skin after weight loss, firm loose skin, tighten loose skin, skin care after weight loss, treat hanging skin Banana skin care recipes Bananas contain high calorie and are very useful for skin care. An excellent beauty product for skin, banana is enriched with lots of fibers, vitamin C and potassium. So, some home-made skin care recipes made with banana have been illustrated here to help you with your skin care. Banana is beneficial for health related problems too, and should be consumed to avoid heart disease and kidney stones. Anyways coming back to the beauty part of it, follow these instructions on how to make skin care recipes with bananas. To prevent wrinkles Mash a banana in a bowl. Add two tablespoons of fresh cream, which is easily available in the market, along with one tablespoon of honey and oat flour each. Blend it well in a mixer till it becomes a smooth paste. Apply the paste all over your face and leave it for half-an-hour. After that, rinse your face with warm water, towel dry and dab some rose hydrosol on your skin. This face mask will give proper nourishment to your face and help remove fine lines and wrinkles. It also prevents early ageing leaving you with a younger looking skin. For a radiant look You need a ripe banana cut into halves, two tablespoons each of ground oats and whole wheat flour, a pinch of nutmeg powder and fresh cream. Mix all the ingredients well into a fine paste. As above, spread the mask on your face, let it stay on for some time, rinse it off and finally pat dry with a soft towel. Each ingredient has its own effect on your skin and the whole combination leaves a glowing effect on the skin. To prevent skin tan Banana also acts as a great catalyst to avoid skin tanning and can help protect your skin from sun damage. In a bowl, mash a small banana and add to it some fullers-earth and lemon juice. Pour water into it or you can also use fresh cream or milk instead to make a thick paste. Adding in a pinch of saffron will add up to the benefits. This facial mask is awesome for those who want to remove sun tan. The nutrients in banana prevent skin tanning and adding fullers-earth doubles up the sun-damage fighting effect of this mask. Banana skin care recipes, banana mask to fight sun tan, banana mask to prevent wrinkles, banana mask for a radiant and glowing skin Article 7 How to get rid of brown skin spots Brown skin spots or sun spots can be easily removed with the help of a few skin care tips. Brown skin spots can be really irritating when they start appearing due to prolonged exposure to the sun. Follow these quick and easy instructions presented here to get a blemish free skin. Find out the causes behind those brown spots. The usual reason is the harmful effect of UVA and UVB rays present in sunlight, which also cause ageing. If your brown spots are because of sun damage the most likely affected areas will be face, neck and arms as these are more exposed to direct sun rays. The cosmetic care Try to avoid direct sunlight to prevent damages and wrinkles. Always use a strong sunscreen before stepping out, and make sure to buy those which do not clog the skin pores. Also try and opt for oil-free sunscreen lotions to avoid the greasiness, if your skin is oily. Apart from the sunscreen you need to focus on special skin care products available for treating brown spots. Some of the best examples include Olay’s UV Defense Regenerating Lotion which is also excellent for anti-ageing – minimizing all sorts of age spots and fine lines. Another one is Lotus’s Herbal Safe Sun-block Cream which is sweet smelling, water-proof and non greasy, perfect for hot and humid weather. It’s ideal for all types of skin, particularly for oily skins. Natural remedies You can also opt for natural remedies. Lemon juice is worth a try as the natural acids in lemon help reduce brown spots. This may take longer for the spots to fade out but one thing is guaranteed that you will not have any side effects associated with store bought beauty products. It sure is useful and will get you reasonable good results over a few weeks of regular usage. Exfoliating holds an answer Dead skin exfoliation is a must in your skin care routine, if you’re troubles with brown spots on your skin. When you scrub the skin, the upper layer of the dead skin gets removed and this process is very useful in fading and completely removing brown spots or sun spots. Prevent brown skin spots, treating brown spots, natural remedies for brown sun spots Article 8 Make your skin glow in less than 10 mins. Facial skin care is perhaps the most important among all the aspects of skin care. The face epitomizes beauty and inner health. If your face glows, you will automatically feel good. Here are some quick and easy recipes to make your skin glow in less than 10 mins. Honey based beauty recipes Make a mixture of egg white and honey and apply it to your face for just ten minutes. It helps remove sun tan, and leaves you with a glowing skin. Another quick face pack you can make with honey is by mixing in some powdered oats, yogurt and ground almonds with honey. Leave it on your face for about ten minutes after applying. Rinse off with lukewarm water. Pat dry with a towel and you’ll get an instant shine. Also you can prepare a cleansing solution with tomato juice, carrot juice and honey. Apply the mixture gently all over your face and wash off after ten minutes. Lemon Based recipes to make your skin glow A mixture made of grapes, lemon juice and egg white, where lemon juice whitens your skin tone. Grapes help in softening the skin, egg whites add firmness to the skin and the lemon does the bleaching. This is a good mask for oily skin. Those who have dry skin often lack the brightness on their face and the skin looks dull. An excellent home-made moisturizing recipe can be made for such skin types by blending in honey, lemon and vegetable oil together. Apply for few minutes and you’ll love the glow it leaves on your skin. Cleansing is an essential step of skin care. Mix cucumber juice with milk, blend well. It acts as a natural cleanser. Good for glow. And when you’re in a hurry try this simple trick, rub your face with lemon wedges for a few minutes and then wash off with cold water. It’s easy and can ad an instant glow to your face; however it’s not suggested for women with dry skin. Milk based recipes for a glowing skin For a naturally glowing skin, take some powdered orange peels and mix them with milk. It works as bleach as well as a natural exfoliating agent. Another great face pack can be made by putting a pumpkin slice, egg yolk and milk into a blender to make a smooth paste. And in less than ten minutes you can enjoy a glowing and radiant skin. Recipes for a glowing skin, honey skin recipes, milk beauty recipes, how to make your skin glow Article 9 6 tips to preventing skin from cancer The key to prevent skin cancer is to avoid direct sunlight to come in contact with your skin. Whenever you are stepping out, try and make sure that you wear clothes in which the sun rays cannot penetrate much and come in contact with your skin. Go for long-sleeved attires and always carry an umbrella whenever you are out in the sun. Also it is very important to use a good sun-block. Sunscreen lotions or creams with a high sun protection factor, which is normally mentioned as SPF on the pack, will give you good protection against the harmful UV rays. Always look for SPF 15 or more to get the maximum protection. Some more tips to preventing skin from cancer The sun rays are strongest between 11 a.m to 3 p.m., and as far as possible you must avoid stepping out in the sun during these hours. However, if you have to step out then you must wear sunglasses as well apart from carrying an umbrella or a wide-brimmed hat. You should also be aware of the risk factors causing skin cancer. Those who have fair skin are at higher risk of having skin cancer. Prolonged working or playing under the sun can cause skin cancer. Increase water intake during summer to keep your body and skin hydrated. Also it is wise to carry a small bottle of water in your bag whenever you are out. Excessive sweating during summer reduces the water content in your body. Dehydrated skin is more prone to suffering sun damage. The harmful ultraviolet rays namely UVA rays and UVB rays also reach the pools, at least a foot below the water surface of the pool. So wearing a waterproof sunscreen for swimming isn’t such a bad idea. If you think that on a rainy or cloudy, it’s not necessary to protect your skin from sun rays, you are terribly wrong. The sun rays can pass through the clouds and reach your skin. That’s why you must always keep in mind that whenever you are stepping out in the daytime; you must always take precautionary measures to prevent skin cancer. And last but not the least; eat foods that will strengthen the inner defense of your body, so as to minimize the effects of sun damage to your skin. There are several cancer fighting foods that can help you guard against skin damage. Prevent skin cancer, skin care tips, skin protection tips, guard your skin, avoid skin cancer Article 10 Whiten your skin naturally There are some easy steps to whiten your skin naturally. All you need to do is follow these simple and easy steps. Wash your face gently with a soap-free face-wash and then gently rub with a soft cotton cloth to remove the dead skin layer on the surface of your face. Exfoliating dead cells is very important and this is the first step to whiten your skin naturally. Natural cleansing and bleaching Mix in some tomato juice with lime juice, and store this preparation in a bottle in your refrigerator. If you don’t have ready tomato juice, put one tomato and juice of a lime in a blender. Make it a habit of apply this to your face every morning and leave it on the skin for 15 minutes before washing it off. You can put the remaining mask in a tight container and store it in a refrigerator so that you can use it regularly. After 15 minutes, wash off your face using a face wash and wipe your face gently with a cotton cloth. This gentle scrubbing with the cloth once again will remove any remaining dead skin. The bleaching and deep cleansing properties of tomatoes and lime will help whiten your skin tone. Bet time masks Also at night before you go to bed, apply a mask made of honey and lemon juice to moisturize your face. Take one teaspoon honey and lemon juice each and blend it well in a vessel. Put the paste on your face and leave for 15 minutes. Follow a similar routine by rinsing off your face with lukewarm water followed by using a face wash and removal of dead skin cells with the help of a cloth. Deep exfoliation Once a week you should go in for deep exfoliation of the skin. To make your own homemade scrub, take one tablespoon of white granular sugar and olive oil each and mix them well. Exfoliate your skin with this mixture once a week. Use your fingers to scrub your skin, and remember to move your fingers in a circular motion. Cosmetic solutions Another way to lighten your skin tone is by using organic aloe vera gel. You should use it twice a day, morning and night to get the best results. Aloe vera acts as a moisturizer that helps whiten the skin tone and it also has amazing cooling effect on the skin. This will help in reducing skin irritation too. Skin whitening solution, skin whitening recipes, natural skin whitening, lighten skin tone
The Essence Of Human Resource Management Theory Management Essay
python assignment help According to Martyn Shuttleworth (2009), literature review is a critical and in depth evaluation of research in which all sides of an argument must be clearly explainted, and areas of agreement and disagreement should be highlighted. In order to deal with the objectives and question proposed in the chapter 1, the author is going to find related theories in academic journals both online and paper, and other academic sources to provide the supervisor as well as readers a comprehensive overview of why the author is pursuing the research. In the chapter, the definition, components and practice of human resource management, human resource management in Vietnam and SMEs will be presented. In addition, the author will address the problems and find solutions to improve human resource management. 2.1: Human resource management definition There have been many lessons and also so much research both national and interational on the human resource management, which are widely applied in enterprises. And these primarily concentrate on the areas including the concept of human resource management, functions of human resource management and its applications. An debate on what is the essence of human resource management theory is still ongoing conversation. A review and research agenda put forth by Guest (1997) has endeavoured to pull all those arguments together. He indicates that there are diverse theories about human resource management including illustrative, strategic and normative. Firstly, descriptive theory states that the important inputs of an alternative of human resource management policy and practice such as creating employee influence, enforcing human resource flows and establishing incentive reward systems will influence on four key effects, which are commitment, competence, congruence and cost effectiveness. These leading to they will produce low labor turnover, loyal and faithful employees, who will commit to build up an organization’s efficiency. This statement is also presented by Beer et al (1984) and Beaumont (1993). Secondly, strategic theory suggests that a good coordination between business strategy, human resource policy and practice will strengthen enterprises’ performance. Finally, normative theory describes a set of value that indicates human resource management practice applied to gain normative targets of high commitment to the enterprise. This will affect the performance of enterprises. Definition of human resource management is still in argument. Boxall and Purcell (2003) argue that this definition is affected by three issues. Firstly, human resource management is derived from a range of antecedents and depends on the stance and philosophy of the analyst. Secondly, it contributes to the analysis of the employment relationship, and is reliant upon context. Finally, the significance of human resource management is variable, which emphasize people, strategy, employment relationships etc. In order to emphasize human resource management, Redman and Wilkinson (2006) compare it as the utilization of individuals to achieve an organization’s objectives. People management not only critical to business performance but also much more significant than priority over quality, technology, competitive strategy or R
need short answer for these four question
need short answer for these four question.
I’m working on a finance discussion question and need support to help me learn.
How do you make decisions that are expected to generate income?At different stages of your life, you will evaluate investment options based on the expected cash flows that they are likely to produce – a process that hopefully will help you to make informed decisions. Think about the various way you might invest money to generate income in the future, and how you will make these types of decisions. For this assignment, suppose that you have been given $10,000 with the requirement that you “invest” it in one of the 3 different options below. Research the expected return and associated risk for each of the following:Pay down your student loan or credit card debt. Although this is not technically an investment, it is effectively the same as earning a “risk-free” rate of interest. Alternatively, you can keep the cash in a riskless (FDIC insured) bank account. Current rates are available on a number of different sites such as Bankrate.com.Invest in any stock(s) of your choice. Research the company on Yahoo Finance or other financial site, and get statistics regarding the expected risk and return for this investment. Be very specific about why you selected this company.Invest in a real estate rental property. Research property prices, rents, and expenses for residential income properties or get basic information from a property management site such as Mashvisor or Roofstock. Note that a “cap rate” or “cash-on-cash” return is like a dividend yield for a stock, and is calculated as net operating income (rental income less expenses) divided by the price.There are no wrong answers, but you must justify your opinions using the concepts that you have learned in this course. Be sure to include all factors used in making your evaluations, and be specific about your conclusions. To receive full credit, your answers must be well thought out and well-written.Answer ALL 4 questions below:Before making any calculations, which option appeals to you the most?What methods would you use to evaluate these options? Compare each option in terms of current yield, potential for appreciation, and estimate an approximate long-term total return.Which option offers the best potential return given its level of risk? Which one would you choose given your level of risk aversion? Explain in detail.What sort of capital investments do you think you might make in the future? What other investments (such as owning your own company or investing in a start-up) would you consider? Why? Are there any factors in addition to monetary gain that you would consider?Your score will be determined by your word count (200 word minimum), completely answering all questions, the accuracy of the information you provide, and how well-written your answers are (see rubric below).
need short answer for these four question
Types Of Substitution Reactions Biology Essay
Types Of Substitution Reactions Biology Essay. In a substitution reaction, a functional group in a particular chemical compound is replaced by another group .In organic chemistry, the electrophilic and nucleophilic substitution reactions are of main importance. Organic substitution reactions are classified into depending on whether the reagent that brings about the substitution is considered an electrophile or a nucleophile, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical or whether the substrate is aliphatic or aromatic. A reaction can be made faster or slower by taking into consideration the temperature and the solvent we are using.A good example of a substitution reaction is the photochemical chlorination of methane forming methyl chloride. Nucleophilic substitution What is a nucleophile Nucleophilic substitution happens when the reagent is a nucleophile, which means the attacking species is a nucleus loving species .it is itself negatively charged or has a lone pair. Such species get attracted to positive or electron deficient carbon centres.. A nucleophile reacts with an aliphatic substrate in a nucleophilic aliphatic substitution reaction. These substitutions can be of two dofferent mechanisms: unimolecular nucleophilic substitution (SN1) and bimolecular nucleophilic substitution (SN2). The SN1 mechanism has two steps. In the first step, the leaving group leaves, forming a carbocation. In the second step, the nucleophilic species attacks the carbocation and forms a sigma bond. This mechanism can result in either inversion or retention of configuration. An SN2 reaction has just one step. The attack of the reagent and the expulsion of the leaving group occurs simultaneously. This mechanism always results in inversion of configuration. When the substrate is an aromatic compound the reaction type is nucleophilic aromatic substitution. Electrophilic substitutions What is an electrophile An electrophile is a electron loving species, it itself is positively charged and wants to stabilize itself by making a sigma bond with the electron rich carbon centre. Electrophiles are involved in electrophilic substitution reactions and particularly in electrophilic aromatic substitutions. SN1 REACTION The SN1 reaction is a substitution reaction. “SN means nucleophilic substitution and the “1” represents the fact that the rate-determining step is unimolecular . Carbocation intermediate is formed in this reaction .It is seen that tertiary carbocations are very stable due to I effect and thus go for SN1 Reaction. With primary alkyl halides, the alternative SN2 reaction occurs. As primary Alkyl Halides mostly Form primary carbocation which is very unstable and thus have to go through SN2 Substitution reaction. Mechanism An example of a reaction taking place with an SN1 reaction mechanism is the hydrolysis of tert-butyl bromide with water forming tert-butyl alcohol: This SN1 reaction takes place in three steps: Formation of a tert-butyl carbocation by separation of a leaving group (a bromide anion) from the carbon atom: this step is slow and reversible. Nucleophilic attack: the carbocation reacts with the nucleophile. If the nucleophile is a neutral molecule (i.e. a solvent) a third step is required to complete the reaction. When the solvent is water, the intermediate is an oxonium ion. This reaction step is fast. Deprotonation: Removal of a proton on the protonated nucleophile by water acting as a base forming the alcohol and a hydronium ion. This reaction step is fast. WHY THIS REACTION OCCURS Bulky atoms(methyl, ethyl) surrounding the carbon atoms mostly allow SNI reaction. As the bulky alkyl halides are attached to the central carbon atom,it is both stabilized by hyperconjugation and In ductive effect. The SN1 mechanism therefore dominates in reactions at tertiary alkyl centers and is further observed at secondary alkyl centers in the presence of weak nucleophiles. SN2 REACTION The SN2 reaction (also known as bimolecular nucleophilic substitution or as backside attack) is a type of nucleophilic substitution, where a lone pair from a nucleophile attacks an electron deficient electrophilic center and bonds to it, expelling another group called a leaving group. Thus the incoming group replaces the leaving group in one step. Since two reacting species are involved in the slow, rate-determining step of the reaction, this leads to the name bimolecular nucleophilic substitution, or SN2. Among inorganic chemists, the SN2 reaction is often known as the interchange mechanism. REACTION MECHANISM The reaction most often occurs at an aliphatic sp3 carbon center with an electronegative, stable leaving group attached to it – ‘X’ – frequently a halide atom. The breaking of the C-X bond and the formation of the new C-Nu bond occur simultaneously to form a transition state in which the carbon under nucleophilic attack is pentacoordinate, and approximately sp2 hybridised. The nucleophile attacks the carbon at 180 to the leaving group, since this provides the best overlap between the nucleophile’s lone pair and the C-X s* antibonding orbital. The leaving group is then pushed off the opposite side and the product is formed. If the substrate under nucleophilic attack is chiral, this can lead, although not necessarily, to an inversion of stereochemistry, called the Walden inversion. SN2 reaction of bromoethane with hydroxide ion. The products are ethanol and a bromide ion. In an example of the SN2 reaction, the attack of OH- (the nucleophile) on a bromoethane (the electrophile) results in ethanol, with bromide ejected as the leaving group. SN2 attack occurs if the backside route of attack is not sterically hindered by substituents on the substrate. Therefore this mechanism usually occurs at an unhindered primary carbon centre. If there is steric crowding on the substrate near the leaving group, such as at a tertiary carbon centre, the substitution will involve an SN1 rather than an SN2 mechanism, (an SN1 would also be more likely in this case because a sufficiently stable carbocation intermediary could be formed.) In coordination chemistry, associative substitution proceeds via a similar mechanism as SN2. FACTORS AFFECTING REACTION 1) The Basicity of the Leaving Group. By comparing the relative SN2 reaction rates of compounds with atoms in the same periodic group (the halides, for example), results show that the ability as a leaving group during an SN2 reaction depends on its basicity. In general, the weaker the basicity of a group, the greater its leaving ability. For example, the iodide ion is a very weak base and because it is so, it is the most reactive. Weak bases do not hold their electrons tightly, making it easier for their bonds to be broken. In contrast, the fluoride ion is a stronger base than the other halides and, therefore, the least reactive. In fact, the fluoride ion is such a strong base that compounds involving them essentially do not undergo SN2 reaction. Looking at the periodic table, relative basicity decreases down a group. (Stronger Base) F- > Cl- > Br- > I- (Weaker Base) 2) The Size of the Nucleophile. How readily a compound attacks an electron-deficient atom also affects an SN2 reaction. As a rule, a negatively charged species (e.g. OH -) are better nucleophiles than neutral species (e.g. H2O, water). There is a direct relationship between basicity and nucleophilicity: stronger bases are better nucleophiles. Acidity, the ability of an atom to give up a proton (H ), is comparatively relative in molecules whose attacking atoms are approximately the same in size, the weakest going toward the left side of the periodic table. If hydrogen were attached to second-row elements of the periodic table, the resulting compounds would have the following relative acidities: (Weaker Acid) NH3 < H2O < HF (Stronger Acid) If each of these acids were to give up a hydrogen, the result would be its conjugate base, and the relative strengths will reverse. The stronger base now moves toward the left side of the periodic table. (Stronger Base) -NH2 > HO- > F- (Weaker Base) Elements increase in size down the periodic table. Although basicity decreases down the periodic table, nucleophilicity increases as size increases depending on the solvent used. 3) Solvent. If a reaction is carried out in a protic solvent, whose molecules have a hydrogen bonded to an oxygen or to a nitrogen, the larger atom is a better nucleophile in an SN2 reaction. In other words, the weaker base is the better nucleophile in a protic solvent. For example, the iodide ion is better than a fluoride ion as a nucleophile. However, if the reaction is carried out in an aprotic solvent, whose molecules do not have hydrogen bonded to an oxygen or to a nitrogen, then the stronger base is the better nucleophile. In this case, the fluoride ion is better than the iodide ion as a nucleophile. 4) Sterics. Steric hindrance is any effect of a compound due to the size and/or arrangement of its substituent groups. Steric effects affect nucleophilicity but does not affect base strength. A bulky nucleophile, such as a tert-butoxide ion with its specific arrangement of methyl groups, is a poorer nucleophile than an ethoxide ion with a straighter chain of carbons, even though tert-butoxide is a stronger base. Types Of Substitution Reactions Biology Essay
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