Periodic Table A way of organising the elements.

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1 Periodic Table A way of organising the elements

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4 1828 Berzelius introduce letters to symbolize elements. 1829 Döbereiner devoloped “triads” groups of three elements with similar properties. Cl – Br - I, (the properties of Br are between Cl and I) Ca – Sr - Ba Li-Na-K 1864 Newlands arranged the known elements (around 60) in order tof atomic weights and observed similarities between the first and ninth elements, the second and tenth elements etc 1869 Lothar Mayer ve Dmitri Mendeleyev produced their periodic tables simultaneously 1896 William Ramsay discovered the noble gases. 1913 Henry Moseley, determined the atomic number of each of the elements.

5 Mendeleyev Periyodik Tablosu Produced a table based on atomic weights and arranged periodically with elements with similar properties under each other. Left gaps for unknown elements and predicted their properties.

6 Modern Periyodik Tablo Elements are arrangednin the order of increasing atomic numbers and there is a periodic repitition of these elements. The basis of the periodic table is the electron configurations of the elements. Each horizontal row is called a a period. Each vertical column in the periodic atble is called a group. The chemical and physical proprties of the elements in a group are similar.

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8 Nobelium Mendelevium Lawrencium Dubnium Einsteinium Californium Americium Polonium Francium Krypton Neptunium Which of the followings are elements?

9 The boiling points of HCl and HI are : -84.9 o C and -35.4 o C respectively. Predict the boiling point of HBr? The boiling point of PH 3 is : -87.4 o C and the boiling point of SbH 3 is: -17.1 o C. Can you predict the boiling point of AsH 3 ?

10 Atomic radius (atomic size) is the distance between the nucleus and outermost electron.but the electron clouds around atoms have no specific boundaries. What’s usually done is to define an atom’s radius as being half the distance between the nuclei of two identical atoms when they are bonded together. -Covalent radius -Metalic radius -Van der waals radius - ionic radius

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15 Arrange the following in order to increasing radius. a)Li, K, Na b)b) Se 2-, Rb +, Br - c)c) O 2-, F -, N 3-

16 Which atom in each of the following pairs would you expect to be larger? Explain. (a) Mg or Ba (b) W or Au (c) Si or Sn (d) Ce or Lu

17 The amount of energy necessary to remove the highest-energy electron from an isolated neutral atom in the gaseous state is called the atom’s ionization energy, abbreviated. For hydrogen atoms, 1312.0 kJ/mol is needed. Ei or I I= R h x Z effective 2 / n 2 An element’s electron affinity, is the energy change that occurs when an electron is added to an isolated atom in the gaseous state. Ionization energy deals with the loss of electrons, electron affinity deals with the gain of electrons.

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19 Z eff = Z – S I = R H n2n2 Z 2 effective valence electrons are the electrons that occupy the outer shell (principal shell number (n)) of an atom. Core electrons are the electrons in inner shells.

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21 Arrange the elements Se, Cl, and S in order of increasing ionization energy Arrange the following elements in order of increasing first ionization energy. i) 14 Si, 16 S, 12 Mg ii) 8 O, 9 F, 16 S

22 Elektronegativity : is a measure of an atom’s ability to attrac electrons from a covalent bond Electronegativity: is a relative ability of atoms to attract electrons in a chemical bond

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25 The atomic mass unit By the international agreement (amu) was standardized against the carbon-12 atom. (atomic mass of C-12 = 12 amu.= 1,66054 x 10 -24 gram The average atomic mass An element’s atomic mass is the weighted average of the isotopic masses of the element’s naturally occurring isotopes. The average atomic mass of each element is also referred to as its atomic weight. Naturally occurring carbon is 98.892% 12 C and 1.108% 13 C. The mass of 12 C is 12 amu, and that of 13 C is 13.00335 amu. Therefore, the average atomic mass of carbon is: (0.98892)*(12 amu) + (0.01108)*(13.00335 amu) = 12.011 amu

26 Chlorine has two naturally occurring isotopes 35 Cl: with a natural abundance of 75.77% and an isotopic mass of 34.969 amu, and 37 Cl with a natural abundance of 24.23% and an isotopic mass of 36.966 amu. What is the atomic mass of chlorine?

27 Chlorine has two naturally occurring isotopes 35 Cl: with a natural abundance of 75.77% and an isotopic mass of 34.969 amu, and 37 Cl with a natural abundance of 24.23% and an isotopic mass of 36.966 amu. What is the atomic mass of chlorine?

28 Soru: Magnezyum atomunun doğal izotoplarını doğada bulunma yüzdeleri ve kütleleri aşağıdaki gibidir. Mg un ortalama atom kütlesini hesaplayınız. 23,985 %78,99 24,986 %10,00 25,983 %11,01

29 Atomic mass Molecular weightFormula weight The average atomic mass of each element is also referred to as its atomic weight. Molecular weight is the sum of the atomic weights of all the atoms in a molecule. Formula weight is the sum of the atomic weights of all atoms in a formula unit. Avagadro Number The number of atoms in 12g of 12 C is called Avagadro’s number, N A = 6.022137 x 10 23 Mole One mole is the amount of substances which contains Avagadro’s number of particle. Molar mass of any particle is the mass of 1 mole of that substance

30 Calculate the molecular weight of CCl 4 (C :12.01 Cl : 35.45) = (atomic weight of C) + (4 x atomic weight of Cl) = 12.01 + 4 x 35.45 =153.8

31 Kimyasal FormülBileşikler sembolize eder. Kimyasal formül; -bileşikte bulunan elementleri -her bir elementin sayısını gösterir Basit formülMolekül formülüYapısal Formül Bileşikteki atomların birbirine oranının en küçük değerde ifade eder. Bir moleküldeki atomların gerçek sayısını gösterir. Atomların birbirlerine nasıl bağlandığını gösterir

32 Moleküler Bileşiklerin Formüllerinin Yazılması Bileşiğin Yüzde Bileşimini KullanarakYakma Analizleri

33 Yüzde Bileşim Bileşiğin 100gramında ki elementlerin gram miktarını gösterir.

34 Basit Formül Bulma Elementlerin Bileşik içinde verilen kütle oranları mol sayısına çevirilir Herbir elementin mol sayısı, bulunan mol sayıları içindeki en küçük mol sayısına bölünür Elde edilen rakamlar ile basit formül yazılır (rakamlar tam sayı olmalıdır, bunun için uygun katsayı ile carpma yapılır)

35 Soru: bir organik bileşiğin yapısında kütlece %40,00 Karbon, %6,66 hidrojen ve %53,34 oksijen vardır. Bileşiğin kaba formülü nedir?

36 Soru: 25gramında 6,64g K, 8,84g Cr ve 9,52g Oksijen içeren bileşiğin basit formülü nedir?

37 Basit formülden Molekül formülü Bulma Eğer bir bileşiğin basit formülü ve bileşiğin mol ağırlığı biliniyorsa, molekül formülü bulunabilir. Basit formülün ağırlığı x katsayı = mol ağırlığı

38 Soru: laktik asit C-H-O atomlarından oluşur. Bir laktik asit örneği yapılan analiz sonucu 25,200gramı 10,085g C, 13,440g oksijen içerdiğine ve laktik asitin mol kütlesi 90,0g olduğuna göre laktik asidin molekül formülünü bulunuz.

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40 Yakma Analizlerinden Molekül formülü Bulma

41 5gram etilalkol yakıldığında 9,55g CO2 ve 5,87g H2O oluşmaktadır. Etil alkolün basit formülü nedir?