Periodic Table

1. Periodic Table A way of organising the elements

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.

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

9. The boiling points of HCl and HI are : -84.9oC and -35.4oC respectively. Predict the boiling point of HBr? The boiling point of PH3 is : -87.4oC and the boiling point of SbH3 is: -17.1oC. Can you predict the boiling point of AsH3?

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 todefine an atom’s radius as being half the distance between the nuclei oftwo identicalatoms when they are bonded together. -Covalent radius -Metalic radius -Van der waals radius - ionic radius

14. Arrange the following in order to increasing radius. • Li, K, Na • b) Se2-, Rb+, Br - • c) O2-, F -, N 3-

15. 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

16. 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= Rh x Zeffective2 / n2An 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.

17. Ionization energy deals with the loss of electrons, electron affinity deals with the gain of electrons.

18. 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. Z2effective Zeff = Z – S I = RH n2

20. 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) 14Si, 16S , 12Mg • ii) 8O, 9F, 16S

21. 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

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

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

27. Soru: Magnezyum atomunun doğal izotoplarını doğada bulunma yüzdeleri ve kütleleri aşağıdaki gibidir. Mg un ortalama atom kütlesini hesaplayınız.23,985 %78,9924,986 %10,0025,983 %11,01

29. Calculate the molecular weight of CCl4 (C :12.01 Cl : 35.45) • = (atomic weight of C) + (4 x atomic weight of Cl) • = 12.01 +4 x 35.45 • =153.8

32. Yüzde Bileşim • Bileşiğin 100gramında ki elementlerin gram miktarını gösterir.

33. 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)

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

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

36. 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

37. 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.

39. Yakma Analizlerinden Molekül formülü Bulma

40. 5gram etilalkol yakıldığında 9,55g CO2 ve 5,87g H2O oluşmaktadır. Etil alkolün basit formülü nedir?