THE PERIODIC TABLE HISTORICAL BACKGROUND The idea that all things are elements or combinations of elements can be found in the writings of the ancient Greeks and other early peoples. Although this idea may seem simple‚ it is very difficult to decide if a substance is indeed an element or a compound. There were twelve chemical elements discovered in ancient times‚ but it was not known that they were elements. Another 76 elements were discovered between 1557 and 1925. Many mistakes were made in
Free Periodic table Chemical element Atomic number
Chemical Bonds Chemical Bond: is the force that holds atoms together in a compound. They form because they lower the potential energy of the charged particles that compose atoms. Chemical bonds can be broadly classified into two types: Ionic and Covalent. Ionic: metal & nonmetal Metals have a tendency to lose electrons and nonmetals have a tendency to gain them. The metal atom becomes a cation and a nonmetal becomes an anion. The oppositely charged ions attract one another and form an ionic compound
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Explore key information about the chemical elements through this periodic table | Group | 1 | 2 | | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | Period | | 1 | 1H1.008 | | 2He4.0026 | 2 | 3Li6.94 | 4Be9.0122 | | 5B10.81 | 6C12.011 | 7N14.007 | 8O15.999 | 9F18.998 | 10Ne20.180 | 3 | 11Na22.990 | 12Mg24.305 | | 13Al26.982 | 14Si28.085 | 15P30.974 | 16S32.06 | 17Cl35.45 | 18Ar39.948 | 4 | 19K39.098 | 20Ca40.078 | | 21Sc44.956 | 22Ti47.867 | 23V50.942 |
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BONDS Bonds pay fixed coupon (interest) payments at fixed intervals (usually every six months) and pay the par value at maturity. Par value = $1‚000 Coupon = 6.5% or par value per year‚ or $65 per year ($32.50 every six months). Maturity = 28 years (matures in 2032). Issued by AT&T. Types of Bonds Debentures - unsecured bonds. Subordinated debentures - unsecured “junior” debt. Mortgage bonds - secured bonds. Zeros - bonds that pay only par value at maturity; no coupons. Junk bonds - speculative or
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|Ruskin Bond | |[pic] | |Ruskin Bond in a Meet the Author program at Sharjah International Book Fair‚ | |23 November 2011 | |Born |19 May 1934 (age 78) | | |Kasauli‚ Solan Himachal Pradesh‚ India | |Occupation
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Periodic Table of the Elements I 1. 1 1 2 H H He II 1.00794 3 2. 4. 5. 6. Li Be 9.012182 IV V VI 1.00794 4.002602 5 6 7 8 9 10 N O F Ne B C 10.811 12.0107 13 14 15 Si P 12 Na Mg Al 22.989770 24.3050 26.981538 14.00674 15.9994 18.9984032 20.1797 16 28.0855 30.973761 17 18 S Cl Ar 32.066 35.4527 39.948 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Br Kr 39.0983
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Topic 4 - Bonding 4.1 Ionic bonds 4.1.1 Ionic bond: +ve (cations) and -ve (anions) ions are attracted to each other and form a continuous ionic lattice 4.1.2 Group 1 metals form +1 ions‚ group 2 metals form +2 ions‚ metals in group 3 form +3 ions . Examples : Li+‚ Mg2+‚ Al3+. Greater ease of ionisation Li->Cs is due to the increased electron shielding of the nuclear attraction caused by additional inner shells of electrons. The easier atoms are to ionise‚ the more reactive they
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Government Bonds & E Savings Bonds David A Barton Colorado Technical University Online Government Bonds & E Savings Bonds Retrieved from: Treasury Direct http://www.treasurydirect.gov/BC/SBPrice EE BONDS: $ 50 - $500 - $1‚000 Oct-2001 | | Oct-2004 | | Oct-2007 | | Oct-2010 | Value | | Int. Rate | | Value | | Int. Rate | | Value | | Int. Rate | |
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and it was 21cm long‚ and then she measured her Mother’s foot‚ and it was 24cm long. "I must have big feet‚ my foot is nearly as long as my Mom’s!" But then she thought to measure heights‚ and found she is 133cm tall‚ and her Mom is 152cm tall. In a table this is: Allie Mom Length of Foot: 21cm 24cm Height: 133cm 152cm The "foot-to-height" ratio in fraction style is: Allie: 21 133 Mom: 24 152 So the ratio for Allie is 21 : 133 By dividing both values by 7 we get 21/7 : 133/7 = 3 : 19 And the
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The Periodic Table Notes History of the Periodic Table * Two main contributors * Dmitri Mendeleev * Henry Moseley Dmitri Mendeleev – Russian * 1869: published his periodic table with the 63 known elements * Arranged the first periodic table in order of increasing atomic masses Henry Moseley – British * 1913 revised Mendeleev’s periodic table * Today’s periodic table * Arranged in order of increasing atomic numbers What is the difference between Mendeleev’s
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