Valence Definition in Chemistry

Valence is typically  the number of electrons needed to fill the outermost shell of an atom. Because exceptions exist, the more general definition of valence is the number of electrons with which a given atom generally bonds or number of bonds an atom forms. (Think iron, which may have a valence of 2 or a valence of 3.) The IUPAC formal definition of valence is the maximum number of univalent atoms that may combine with an atom. Usually, the definition is based on the maximum number of either hydrogen atom or chlorine atoms. Note the IUPAC only defines a single valence value (the maximum), while atoms are known to be capable of displaying more than one valence. For example, copper commonly carries a valence of 1 or 2. Example A neutral carbon atom has 6 electrons, with an electron shell configuration of 1s22s22p2. Carbon has a valence of 4 since 4 electrons can be accepted to fill the 2p orbital. Common Valences Atoms of elements in the main group of the periodic table may display a valence between 1 and 7 (since 8 is a complete octet). Group 1 (I) - Usually displays a valence of 1. Example: Na in NaClGroup 2 (II) - Typical valence is 2. Example: Mg in MgCl2Group 13 (III) - Usual valence is 3. Example: Al in AlCl3Group 14 (IV) - Usual valence is 4. Example: C in CO (double bond) or CH4 (single bonds)Group 15 (V) - Usual valences are 3 and 5. Examples are N in NH3 and P in PCl5Group 16 (VI) - Typical valences are 2 and 6. Example: O in H2OGroup 17 (VII) - Usual valences are 1 and 7. Examples: Cl in HCl Valence vs Oxidation State There are two problems with valence. First, the definition is ambiguous. Second, its just a whole number, without a sign to give you an indication of whether an atom will gain an electron or lose its outermost one(s). For example, the valence of both hydrogen and chlorine is 1, yet hydrogen usually loses its electron to become H, while chlorine usually gains an additional electron to become Cl-. The oxidation state is a better indicator of the electronic state of an atom because it has both magnitude and sign. Also, its understood an elements atoms may display different oxidation states depending on the conditions. The sign is positive for electropositive atoms and negative for electronegative atoms. The most common oxidation state of hydrogen is 8. The most common oxidation state for chlorine is -1. Brief History The word valence was described in 1425 from the Latin word valentia, which means strength or capacity. The concept of valence was developed in the second half of the 19th century to explain chemical bonding and molecular structure. The theory of chemical valences was proposed in an 1852 paper by Edward Frankland.

High School Dropout Rate Is A Significant Indicator Of...

Introduction: High school dropout rate is a significant indicator of future success in life. For high school dropouts, it is harder to find jobs and earn as much money as their graduated peers. On the outside looking in, not being able to graduate is usually associated with school performance, socioeconomic status, parents’ education level and/or lack of motivation. Moreover, there are also underlying factors of race and gender and they both affect performance in high school immensely. In order to study dropout rates, focus should be put on the group of students at risk of dropping out. In terms of high school dropout rate, Oakland Technical High School has distinct differences between different races and sexes. Hispanics have lower†¦show more content†¦Literature Review: Sociologists and psychologists have studied and documented high school dropout rate for many decades. Their focus has been put on statistics of different races/ethnicities, age groups and gender as well as underlying factors of why people drop out. Comparing the dropout statistics of different races is a common theme amongst many sociologists’ studies. The extent of their research addresses many significant aspects of high school drop out but fail to shed light on the differences within races between the two genders. In the scholarly paper â€Å"Dropping Out of High School: The Influence of Race, Sex, and Family Background† by Russell W. Rumberger, he analyzes the underlying issues behind why students drop out. There is significance behind studying dropout rate, as students t hat drop out are usually less able than students who graduate high school. Dropouts are more likely to engage in crime, use drugs and/or alcohol, and have earlier marriages. He addresses several issues as to why students drop out as well as differences between why females and males drop out. (Rumberger) Females are more likely to drop out due to marriage and pregnancy while males are more likely to drop out because they do not like school. (Rumberger) This shows immense inequality between the two sexes as men can simply drop out of school because they want to while

John Keats And Bob Dylan Essay Example For Students

John Keats And Bob Dylan Essay Why Judgments Matter, gives many examples of why value judgments are importantin our lives. I feel that value judgments are as equally important and it shouldbe evident why after briefly explaining Friths examples and my own as well. In his first example, Mr. Frith gives insight to David Hares comment, Inthe end, Keats was just better than Bob Dylan. The media, without delay,misjudged the true meaning of Hares statement and transposed it into a debateof value. Although Mr. Frith did not agree with the medias tactics, he didagree with the ?value debate. Mr. Frith Feels that value judgmentsorganize social relations in our life, and he further proves this pointusing an example from popular music. Mr. Frith focuses on views in musicstudies. Judgments about musicians are generally made in two ways. Firstly, isthe elevation of excitement with ?community'(joining of performers and theiraudience). Secondly, aesthetic and ethical sub-tones during community. Thisvalue placed upon the musicians is very important, this is possibly the decidingfactor in the performers career. If more fans come to a concert, then theperformer becomes more popular or valuable. The same goes for the messages sentout by the performer during a per formance. A message that is widely accepted andadorned will attract more fans. I find that the critical analysis of valuejudgments in our lives is of equal importance. I agree with Mr. Frithsfindings and find them to be true in other life settings as well. As individualswe use value judgments to prioritize important characteristics in our life,which shape us into cultural individuals. We place a high judgment on the socialaspect of our culture. Some examples of this include; friendships, personalappearances, and material items. In friendships, we place value judgment onmoral attributes set by others. It is these attributes that we judge to beworthy or unworthy of our friendship. Those of similar moral values tend to findeach other in companionship. In personal appearances, we place value on what werepresent ourselves to be. Higher income families tend to pay more attention tothis value for it is a language in which is unspoken. Financial value of onesappearance and the personal valu e (self esteem) of ones self tend to runparallel. People place different values on the material items they posses. Twofamilies may bring the same income into a household, and posses some of thesimilar materials. However, it is the value they place on their material itemsthat make them different. It is this difference that brings out the subjectiveindividuality. Evaluation is a key cultural activity, according to Frith. Without evaluation we would not be able to set some separation between eachother as individuals, eventually becoming numb to culture as we know it. I feelit is imperative that we evaluate every aspect of our lives, in turn ensuringthe greatest personal happiness. How does one attain a favorite? Not bysuggestion of a higher authority, but by evaluation. Putting value on things andmaking value judgments is what enables us to label what we like and what makesus happy. Without it, we would not be happy.

Malcolm X Persuasive Essay Example For Students

Malcolm X Persuasive Essay The year was 1925, and someone special was born. His birth name was Malcolm Little, however there were big things in store for this child. Born in Omaha, Nebraska. The seventh of eleven children born to Earl Little, an organizer for Marcus Garveys ;quot;back-to-Africa;quot; movement (Comptons encyclopedia online). At age six Malcolms father was murdered. As a result his mother later suffered a nervous breakdown, and the family was separated by welfare agencies (Comptons encyclopedia online). Later in life he would blame these same agencies for destroying his family. He was bounced around from boardinghouses and schools, and dreamed of becoming a lawyer only to be discouraged by his teachers. After leaving school, in the eighth grade, he lived with a relative in Boston, Mass. He shined shoes, worked in a restaurant and on a railroad kitchen crew. In 1942 he moved to a section in New York called Harlem. Where he lived as a hustler, cheating people to make money for himself. He also sold drugs and became a drug addict himself. A rival drug dealer named quot;West Indian Archiequot; ran him out of New York. And he ended up back in Boston. Where he started a burglary ring, which consisted of friend named Shorty, a pretty boy type of fellow named Rudy, a woman that Malcolm dealt with named Sophia and one of her friends (Alex Haley 168). He soon found out that crime does not pay, when he soon got arrested and stolen items were found in his possession. The Negroes of that group was sentenced to eight years, while the whites of the group were sentenced to only two. This put an image in Malcolms head on how the justice system was ran. While in prison. Malcolm was well known to the guards. One time he was asked to state his number, but instead he said he forgot his number. The guards beat him and sent him to the ;quot;darkroom;quot;. In the darkroom he met Brother Bains. Bains was a man everyone respected including guards. He was known as a real man and gave speeches about Islam. Malcolm did not listen at first; however it didnt take him long to listen to the words of black empowerment, spoken by brother Bains. The black Muslims prediction that in the near future a great war would take place in which whites would be destroyed and black people would rule the world through the power of Allah, their creator. To prepare for this Brother Bains preached, the importance of self-restraint, opposed the use of drugs and alcohol, and organized self-help groups. Malcolm Little was converted to this faith. Instead of wasting his time in prison getting into more trouble, he begins to read and broaden his thoughts. As he did this, his mind opens up to knowledge. He also tried to improve in other areas such as appearance and speech. He decided not to associate himself with former friends he got in trouble with, and formed new friendships with people of the same faith. He left prison Malcolm X. An image popped into my head while reading quot;the Autobiography of Malcolm Xquot;(Alex Haley 231). The image of a strong man standing in the middle of stage giving a speech. The year is 1953. At the height of racial tension, the city is Detroit. Malcolm X is giving a speech after a run in with FBI agents concerning the nation of Islams practices, and how their message was being used. He stands on the pulpit, and delivers a message. ;quot;We didnt land on Plymouth rock, my brothers Plymouth Rock landed on us!quot; Its a clear message to his followers. If you want to succeed, first get from under that rock. .u54bd9e09c501f29c4925b492d74645d1 , .u54bd9e09c501f29c4925b492d74645d1 .postImageUrl , .u54bd9e09c501f29c4925b492d74645d1 .centered-text-area { min-height: 80px; position: relative; } .u54bd9e09c501f29c4925b492d74645d1 , .u54bd9e09c501f29c4925b492d74645d1:hover , .u54bd9e09c501f29c4925b492d74645d1:visited , .u54bd9e09c501f29c4925b492d74645d1:active { border:0!important; } .u54bd9e09c501f29c4925b492d74645d1 .clearfix:after { content: ""; display: table; clear: both; } .u54bd9e09c501f29c4925b492d74645d1 { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .u54bd9e09c501f29c4925b492d74645d1:active , .u54bd9e09c501f29c4925b492d74645d1:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .u54bd9e09c501f29c4925b492d74645d1 .centered-text-area { width: 100%; position: relative ; } .u54bd9e09c501f29c4925b492d74645d1 .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .u54bd9e09c501f29c4925b492d74645d1 .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .u54bd9e09c501f29c4925b492d74645d1 .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .u54bd9e09c501f29c4925b492d74645d1:hover .ctaButton { background-color: #34495E!important; } .u54bd9e09c501f29c4925b492d74645d1 .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .u54bd9e09c501f29c4925b492d74645d1 .u54bd9e09c501f29c4925b492d74645d1-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .u54bd9e09c501f29c4925b492d74645d1:after { content: ""; display: block; clear: both; } READ: Of Ambition Essay He insisted that ;quot;black is beautiful,;quot; and that African Americans must take control of their own destiny. As Malcolm was giving a speech at the autobahn in New York City. Three men gunned him down, in cold blood, in front of his wife and children. At the end of Malcolms life. He was a changed man, a man no longer involved with racism although he had a large following he saw an even larger picture. He saw a world where people of all colors and religions could help one another instead of fight one another. His most enduring messages are one of black pride and self-respect, combined with his uncompromising rejection of racism. Bibliography OUTLINE I. Malcolm Little A. The beginning B. Separated from family C. Moving around II. Life of Crime A. Being sentenced to jail B. Introduction to Islam C. Name change to Malcolm X III. Conclusion A. Speech B. His gift