Periodic Table Definition in Chemistry

Periodic Table Definition in Chemistry The periodic table is a tabular arrangement of the chemical elements by increasing atomic number which displays the elements so that one may see trends in their properties. The Russian scientist Dmitri Mendeleev is most often credited with inventing the periodic table (1869) from which the modern table is derived. Although Mendeleevs table ordered the elements according to increasing atomic weight rather than atomic number, his table illustrated recurring trends or periodicity in the element properties. Also Known As: Periodic Chart, Periodic Table of the Elements, Periodic Table of the Chemical Elements Key Takeaways: Periodic Table Definition The periodic table is a tabular arrangement of chemical elements that is arranged by increasing atomic number and groups elements according to recurring properties.The seven rows of the periodic table are called periods. The rows are arranged so that metals are on the left side of the table and nonmetals are on the right side.The columns are called groups. Group contain elements with similar properties. Organization The structure of the periodic table makes it possible to see relationships between elements at a a glance and predict properties of unfamiliar, newly discovered, or undiscovered elements. Periods There are seven rows of the periodic table, which are called periods. Element atomic number increases moving from left to right across a period. Elements toward the left side of a period are metals, while those on the right side are nonmetals. Groups The columns of elements are called groups or families. Groups are numbered from 1 (the alkali metals) to 18 (the noble gases). Elements within a group display a pattern with respect atomic radius, electronegativity, and ionization energy. Atomic radius increases moving down a group, as successive elements gain an electron energy level. Electronegativity decreases moving down a group because adding an electron shell pushes the valence electrons further from the nucleus. Moving down a group, elements have successively lower ionization energies because it becomes easier to remove an electron from the outermost shell. Blocks Blocks are sections of the periodic table that indicate the outer electron subshell of the atom. The s-block includes the first two groups (the alkali metals and the alkaline earths), hydrogen, and helium. The p-block includes groups 13 to 18. The d-block includes groups 3 to 12, which are transition metals. The f-block consists of the two periods below the main body of the periodic table (the lanthanides and actinides). Metals, Metalloids, Nonmetals The three broad categories of elements are metals, metalloids or semimetals, and nonmetals. Metallic character is highest at the bottom lefthand corner of the periodic table, while the most nonmetallic elements are in the upper righthand corner. The majority of chemical elements are metals. Metals tend to be shiny (metallic luster), hard, conductive, and capable of forming alloys. Nonmetals tend to be soft, colored, insulators, and capable of forming compounds with metals. Metalloids display properties intermediate between those of metals and nonmetals. Toward the right side of the periodic table, the metals transition into nonmetals. There is a rough staircase pattern- starting at boron and going through silicon, germanium, arsenic, antimony, tellurium, and polonium- that identified the metalloids. However, chemists increasingly categorize other elements as metalloids, including carbon, phosphorus, gallium, and others. History Dmitri Mendeleev and Julius Lothar Meyer independently published periodic tables in 1869 and 1870, respectively. However, Meyer had already published an earlier version in 1864. Both Mendeleev and Meyer organized elements by increasing atomic weight and organized elements according to repeating characteristics. Several other earlier tables were produced. Antoine Lavoisier organized elements into metals, nonmetals, and gases in 1789. In 1862, Alexandre-Emile BÃ ©guyer de Chancourtois published a periodic table called the telluric helix or screw. This table was probably the first to organize elements by periodic properties. Sources Chang, R. (2002). Chemistry (7th ed.). New York: McGraw-Hill Higher Education. ISBN 978-0-19-284100-1.Emsley, J. (2011). Natures Building Blocks: An A-Z Guide to the Elements. New York, NY: Oxford University Press. ISBN 978-0-19-960563-7.Gray, T. (2009). The Elements: A Visual Exploration of Every Known Atom in the Universe. New York: Black Dog Leventhal Publishers. ISBN 978-1-57912-814-2.Greenwood, N. N.; Earnshaw, A. (1984). Chemistry of the Elements. Oxford: Pergamon Press. ISBN 978-0-08-022057-4.Meija, Juris; et al. (2016). Atomic weights of the elements 2013 (IUPAC Technical Report). Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305

Nathan Bedford Forrest

Nathan Bedford Forrest, one of the military geniuses of American history, was born July 13, 1821 in Bedford County, Tennessee. Nathan Forrest was the son of William and Marian Beck Forrest. Nathan's father Willaim died when he was only 16. Forrest rose from poverty to become a wealthy cotton planter, horse and cattle trader, real estate broker, and slave dealer. Nathan Forrest was perhaps the most interesting and controversial general of the civil war. This almost illiterate backwoodsman was a self-made millionaire who enlisted as a private in the Confederate Army in June of 1861 and with no prior military training rose to the rank of lieutenant general in 1865 and has also been called the greatest cavalry commander of either army. Without military education or training, he became the annoyance of Grant, Sherman, and almost every other Union general who fought in Tennessee, Alabama, or Kentucky. His formula for success was "get there first with the most men." Forrest w!as fe arless and brutal. "War means fightin' and fightin' means killin'," he explained. His nemesis General William Tecumseh Sherman called him "a devil" and declared that Forrest should be "hunted down and killed if it costs 10,000 lives and bankrupts the treasury." It is said that Forrest personally killed 31 men and had 29 horses shot out from under him. Forrest left his mark throughout the Western and at many sites in West and Middle Tennessee. During the years General Nathan Bedford Forrest was a leader he fought in many wars. At the Battle of Fort Donelson, where 13,000 Confederates surrendered to General U.S. Grant, Forrest declared that he had not come to surrender and led his men through swollen rivers and winter weather to the safety of Nashville. At Pittsburgh Landing he charged and routed a line of Union skirmishes by himself in defense of the retreating rebel army. In Murfreesboro, Tennessee he freed a garrison jail

Interior Design Assignment Example | Topics and Well Written Essays - 500 words

Interior Design - Assignment Example With the fascinating variety of experiences, but textural and cultural to dip into, there has never been a better time to be an interior designer, or interior architects as we are often known as. The first and most noticeable challenge that our profession faces is control over the gradual but inexorable dominance of technology. The curricula in colleges are software specific, to the extent that in cases the act of design itself is limited by what can be designed then displayed with the available software. Design firms use colleges like training grounds for their own recruitment, by encouraging instruction in software and technology used by their firm. The use of technology in all its forms is a boon without a doubt, but the challenge is the need to propagate the use of technology as a tool, rather than as a set of design-defining parameters. Another challenge that is faced by the field of interior design is the corporatization of the field, where a relatively small group of design firms amass the resources and the means to dominate every aspect of the profession.. To deal with this, Interior designers have to redefine themselves and the way they project their skills and their profession, so as to enable their potential clients to see the innate value in personal interaction.

Identification of novel human cancer-specific antigens Literature review

Identification of novel human cancer-specific antigens - Literature review Example   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Likewise, opportunities to develop cancer treatment demonstrated promising results (Haffner et al., 2001; Jager, Jager, and Knuth, 2002; Fijak and Meinhardt, 2006; Park, Lin, Nishidate, Nakamura & Katagiri, 2006;   Tabi and Man, 2006;   Ã‚  Hayashi et al., 2007; Meklat et al., 2007; Dakshinamurthy, Ramesar, Goldberg and Blackburn, 2008; Hunder et al., 2008; Old, 2008; Caballero and Chen, 2009; Chen et al., 2009; Dubovsky et al., 2009; Fard and Modaressi, 2009; Vujanovic and Butterfield, 2009). Consequently, pioneering research in the search for effective cancer vaccines has produced cancer/testis antigens such as MAGE, GAGE, and NY-ESO-1 which are currently undergoing clinical trials (Mashino et al. 2001; Bowlus, 2007; Gierstoff and Ditzel, 2008). Each year more cancer/testis antigens are being identified, creating more opportunities for research and increasing the chances of developing cancer vaccines that can be used not only for treatments, but for prevention as well (Jager, Jager, and Knuth, 2002). Also, research on cancer/testis antigens has brought to light important discoveries on how mechanisms of cancer development work at a molecular level (Alters, 2000; Old, 2001; Gjerstoff, Kock, Nielsen and Ditzel, 2007; Delbridge, 2010; Inagaki, Schoenmakers and Baarends, 2010; Suzuki et al., 2010). Moreover, studies on the link between chromosomes and immune responses reveal that some cancers are more prevalent in males than in females. In addition, results also show that females may have higher cancer survival rates but are more susceptible to autoimmune diseases (Libert, Dejager and Pinheiro, 2010). Further research on the role of cancer/testis antigens should be conducted, particularly in determining the mechanisms that initiate cancer in the first place. Also, further studies should be performed to developed better cancer diagnostic methods and combination immunotherapy

Come a-knocking on Deaths door Essay Example for Free

Come a-knocking on Deaths door Essay The Ode is used as a poetic form for philosophical contemplation. Compare two odes by Keats in the light of this observation How much do you agree with the statement: John Keats was unfortunate in his upbringing to some extent? On one hand there was a chance for a budding surgeon but he gave that away to his literary awakening which drew him to write odes such as the ones I am going to analyse. Personally, learning about his life prior to literature, I feel that the situations he dealt with, at such a young age were remarkable but perhaps had he not faced those decisions, he wouldnt have come to write such poetry brimming full with philosophical contemplation. John Keats was born on the October 31st, 1795 in Finsbury Pavement, near the centre of London. He learnt to deal with death from an early age as his father died in an accident when he was only eight years old. Seventeen years later in 1810, his mother died due to consumption, leaving John in the care of his grandmother. Subsequently, under the care of guardians he left school to become an apprentice to a surgeon. Unfortunately, before the completion of his apprenticeship, John had a quarrel with his master and therefore left to pursue a stronger path in literature, deftly in the company of his good friend Cowden Clarke. Three years of receiving scarce and negative feedback on his sonnets and poems, John was once again in the presence of a dying man: this time it was his brother. Tom Keats was also taken by consumption in 1818. Though by this time, distinct signs had begun to show in the decent of Keatss own health. Keats himself was fighting illness and death in his latter years. Despite the fact of his deteriorating wellbeing, Keats continued to delve deeper into love and time. His mental understanding of what lies beyond was perhaps something that I could never even begin to contemplate. His dying wish was to have the words: Here lies one whose name was writ in water, on his gravestone when he died on 23rd February, 1821. Writing his most famous odes in his dying years was a sign of great character; I think that being able to face such a prospect of dying young, his mind matured faster than that of others. Increasingly throughout the odes, I can see that John has indeed spent many thought provoking sessions in front of the artefact he describes. He sees, he feels, he waits and then he writes. The form of poetry which Keats was most celebrated for was the Ode. This style of elaborate and stately lyric poem was lengthened or shortened at the whim of the poet. However, the basic arrangement of the stanzas was patterned in sets of three a strophe and an antistrophe, of which both had an identical metrical scheme, and an epode, which had a structure of its own. Dating back to the Greek choral songs, the ode has appeared in many centuries over the world. Roman poets such as Catullus took the form of poetry to their own meaning. The ode was generally used to express strong emotions that flooded the poets mind at the time, the poet would be transfixed onto the idea and he would try to convey his meaning through the literary form.

An Annotation of The Gift Outright by Robert Frost Essay -- Robert Fro

An Annotation of The Gift Outright by Robert Frost In "The Gift Outright," Robert Frost traces the development of American culture from colonial times to a more present perspective. He tells the American story of colonialism, freedom, westward expansion, and the quest to develop a specifically American culture. In doing this, he focuses on explaining ways in which Americans supported the growth and development of their country and culture. Frost suggests that Americans showed their allegiance to their developing country and culture in several ways: battlefield bravery, commitment of talents to the good of the country, and dedication to expanding the United States' land and power. His reflection on the past is also a call for action in the future. He acknowledges that American culture is still not fully developed and the continued dedication of Americans, like occurred in the past, is required for the United States to recognize her full potential. The Gift Outright By Robert Frost The land was ours before we were the land's. She was our land more than a hundred years Before we were her people. She was ours In Massachusetts, in Virginia, But we were England's, still colonials, Possessing what we still were unpossessed by, Possessed by what we now no more possessed. Something that we were withholding made us weak Until we found out that it was ourselves We were withholding from our land of living, And forthwith found salvation in surrender. Such as we were we gave ourselves outright (The deed of gift was many deeds of war) To the land vaguely realizing westward, But still unstoried, artless, unenhanced, Such she was, such as she would become. The "belonging" discussed in line one immediately establishe... ...een physical and cultural American growth. Although the early country was growing in land and although the Americans had surrendered their talents, Frost ironically says that Americans were still "unstoried, artless, and unenhansed." This final statement of the poem seems to imply that Frost saw that citizens' unity was really created by "the gift outright" of talents and work, but that the American culture they were seeking to make is still unfulfilled. Throughout the poem, Frost does seem to be saying that Americans were making advancements towards creating an American culture, such as when Americans "found salvation in surrender." In the end, though, Frost realizes that America is still "unstoried, artless, and unenhanced" and presents Americans again with the persistent goal of giving themselves outright in order to continue to build a uniquely American culture.

Drug and Crime Prevention Essay

The purpose of the Final Project is for you to demonstrate your understanding of crime prevention programs and the role crime prevention plays in the overall criminal justice system. You may select a crime prevention program that addresses law enforcement, the courts, or corrections; or it may be a comprehensive program that addresses all three. The program may address the adult justice system, juvenile justice systems, or both. For the purposes of this assignment assume, you are preparing a proposal to a city, county, or state governmental body to recommend the implementation of a crime prevention program within their jurisdiction. You need to demonstrate the value of the crime prevention program and its effectiveness in reducing crime thus reducing the overall costs to the jurisdiction or building value that improves the effectiveness of crime prevention to the community justifying the additional expenditures. Your proposal will include: 1. A summary of the jurisdiction (i.e., city, county, or state) and the portion of the criminal justice System your proposal is designed to address. 2. An analysis of the current trends from three comparable cities in population size, utilizing the SARA Model and the Crime Analysis Triangle. (Note: Crime Analysis for Problem Solvers in 60 Small Steps , Steps 7 and 8). You will compare the data from three comparable jurisdictions and compare it to national data. 3. A determination of the appropriate crime prevention strategy for the jurisdiction based on this analysis. 4. A review of academic literature and studies on the various crime prevention programs to address the needs of the community. How does the crime prevention program address social justice issues†¦ To download this material Click this link – https://bitly.com/1wyPezy There is no one to clean up after you and cook healthy meals at college. Some indulgences are okay, but still maintain a nutritious diet, get proper sleep, and take care of yourself and your possessions. Take care of yourself well, study appropriately, attend all your classes and follow a regular schedule. You can get ill from being too stressed or not eating healthy enough.