Periodic Table & Periodic Law

Transcription

1 Periodic Table & Periodic Law

2 Organizing the Elements A few elements, such as gold and copper, have been known for thousands of years - since ancient times Yet, only about 13 had been identified by the year As more were discovered, chemists realized they needed a way to organize the elements s Antoine Lavoisier compiled a list of the 23 known elements 1800 s explosion of known number of elements due to technology advancements

3 Organizing the Elements Electricity & Spectrometers Industrial Revolution Chemists used the properties of elements to sort them into groups. In 1829 J. W. Dobereiner arranged elements into triads groups of three elements with similar properties One element in each triad had properties intermediate of the other two elements

4 History 1860 universal method established for accurately determining masses of elements 1864 John Newlands proposed an organization for the elements Law of Octaves when elements arranged by increasing mass their properties repeat every 8 th element Not generally accepted because it did not work for all elements, but correct dealing w/repeating pattern By 1870 approximately 70 known elements

5 History 1869 Lothar Meyer & Dmitri Mendeleev each showed a connection between mass & properties Mendeleev given credit because 1 st & he went on to demonstrate usefulness of his organization method Arranged elements by increasing mass & similar properties Left blank spaces for future element discoveries

6 History & Periodic Law 1913 Henry Moseley arranged the known elements by increasing atomic number & similar properties Modern table is based on Moseley s arrangement Medeleev Father of the Periodic Table Periodic Law there is a periodic repeating pattern of chemical & physical properties of elements when arranged by increasing atomic # known elements

7

8 Modern Periodic Table Columns called Groups or Families Each group numbered 1-8 followed by an A or B Rows called Periods 7 periods total, beginning with Hydrogen Representative Elements groups 1A - 8A, called this because posses a wide range of chemical and physical properties

9 Modern Periodic Table Transition Elements groups with a B, 1B 8B IUPAC System of numbering 1-18 International Union of Pure & Applied Chemistry Three main classifications for elements Metals Nonmetals Metalloids

10 Areas of the Periodic Table of Elements Major Sections Metals Metalloids Nonmetals Alkali Earth Alkaline Earth Transition Halogens Nobel Gases Other

11 Metals Shiny when smooth & clean, solid at room temp. Good conductors of heat & electricity Ductile & Malleable Most of A elements & all of B elements All elements to left of staircase line 1A = alkali metals & 2A = alkaline earth metals B elements called transition and inner transition Inner divided into lanthanide & actinide series

12 Metals Alkali Metals Group IA or 1 All have 1 valence electron +1 oxidation number Very reactive, can corrode in air Soft, malleable, and ductile Good conductors of electricity Lithium, Sodium, Potassium, Rubidium, Cesium, and Francium Li Na K Rb Cs Fr

13 Metals Alkaline Earth Metals Group IIA or 2 All have 2 valence electrons +2 oxidation Number Reactive elements Be Mg Ca Sr Ba Ra Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium

14 Transition Metals Groups III B VIII B or 3-13 Have 3 major areas: Transition Actinide Series Lanthanide Series + oxidation numbers Hg is only liquid at room temperature

15 Transition Metals Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Ac Rf Db Sg Bh Hs Mt Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

16 B Si Ge As Sb Te Metalloids Have both properties of metals and nonmetals Po Are semiconductors; can conduct electricity on a small scale Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, and Polonium

17 Metalloids Also known as semimetals Elements that are bordered by the stair-step line on the periodic table Elements that have physical and chemicals properties of both metals and nonmetals

18 Nonmetals Upper right side of the table Usually gases or brittle dull looking solids All are gases at room temperature except Br, which is a liquid Poor conductors of heat and electricity Groups IV A VIIA, 4A 8A (14-18) Group 15 has 5 valence electrons, and a 3 oxidation number Group 16 has 6 valence electrons, and a 2 oxidation number C N O F P S Cl Se Br I At

19 F Cl Br I At Nonmetals Group VII A or 17 Halogens Each contains 7 valence electrons -1 oxidation number Fluorine, Chlorine, Bromine, Iodine, & Astatine Called halogens, because they often produce a salt compound Halogen comes from Greek Halos = salt and Gen = born

20 Nonmetals Nobel Gases Group VIII A or 18 Called Nobel or Inert Gases All have 8 valence electrons, except Helium only has 2 Helium, Neon, Argon, Krypton, Xenon, and Radon He Ne Ar Kr Xe Rn

21 Classification of Elements Organization by electron configuration Valence Electrons Atoms in same group have similar chemical properties because they have the same number of valence electrons (rep. elements V.E. s = group number) Ex. in 1A all have 1 valence electron Valence Electrons & Period Energy level of element s valence electrons indicates the period (# electron shells) Ex. Ga = [Ar]4s 2 3d 10 4p 1, in period 4

22 H 1 Li 3 1s 1 1s 2 2s 1 Do you notice any similarity in these configurations of the alkali metals? Na 11 K 19 Rb 37 Cs 55 Fr 87 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 1

23 s 1 Elements in the s - blocks s 2 Alkali metals all end in s 1 Alkaline earth metals all end in s 2 really should include He, but it fits better in a different spot, since He has the properties of the noble gases, and has a full outer level of electrons. He

24 Transition Metals - d block Note the change in configuration. d 1 d 2 d 3 s 1 d 5 d 5 d 6 d 7 d 8 s 1 d 10 d 10

25 The P-block p 1 p 2 p 3 p 4 p 5 p 6

26 Do you notice any similarity in the configurations of the noble gases? 1s 2 1s 2 2s 2 2p 6 1s 2 2s 2 2p 6 3s 2 3p 6 He 2 Ne 10 Ar 18 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 Kr 36 Xe 54 Rn 86

27 F - block Called the inner transition elements f 1 f 2 f 3 f 4 f 5 f 6 f 7 f 8 f 9 f 10 f 11 f 12 f 13 f 14

28 Classification The s, p, d, f block elements S-block = groups 1A & 2A, V.E. s only in s orbitals P-block = groups 3A 8A, contains elements with filled & partially filled p orbitals D-block elements = spans 10 groups, contains the transition metals, filled or partially filled d orbitals F-block elements = spans 14 columns, contains the inner transition elements, filled or partially filled f orbitals

29 Classification s, p, d, f blocks determines the shape of the periodic table of elements As move through periods the principal energy levels increase, as does number of sublevels Period 1 = s block elements Periods 2-3 = s & p block elements Periods 4-5 = s, p, d block elements Periods 6 7= s, p, d, f block elements

30 Periodic Trends Atomic radius Atomic size is defined by how closely an atom lies to a neighboring atom Metals half the distance between adjacent nuclei in a crystal of the element Nonmetals half distance between nuclei of identical atoms that are chemically bonded together Decrease in size as move left-to-right across period Increase in size as move down a group

31 Atomic Size } Radius Measure the Atomic Radius - this is half the distance between the two nuclei of a diatomic molecule.

32 Periodic Trends Ionic Radius Atoms gain or lose electrons to form ions Ion atom or group of atoms with a + or charge Atoms lose electrons, form + ions, become smaller Atoms gain electrons, form ions, become larger Increase as move down a group For metals as move left-to-right decrease and starting in 5A nonmetals decrease as move left-toright

33 Atomic Radii IA IIA IIIA IVA VA VIA VIIA Li Be B C N O F Na Mg Al Si P S Cl K Ca Ga Ge As Se Br Rb Sr In Sn Sb Te I Cs Ba Tl Pb Bi = 1 Angstrom

34 Atomic size and Ionic size increase in these directions:

35 Periodic Trends Ionization Energy An electron must be removed from a neutral atom to form a + ion, which requires energy Ionization Energy energy required to remove an electron from an atom Increase as move left-to-right across a period Decrease as move down a group

36 Period Ionization Energies Group 1 H 2 Mg Symbol Li Be B First Ionization Energy (kj/mol) O F 1000 C N Na Mg Al Si P S Cl K 419 Ca 590 Sc 633 Ti 659 V 651 Cr 653 Mn 717 Fe 762 Co 760 Ni 737 Cu 746 Zn 906 Ga 579 Ge 762 As 947 Se 941 Br 1140 Rb 403 Sr 550 Y 600 Zr 640 Nb 652 Mo 684 Tc 702 Ru 710 Rh 720 Pd 804 Ag 731 Cd 868 In 558 Sn 709 Sb 834 Te 869 I 1008 Cs 376 Ba 503 La * 538 Hf 659 Ta 761 W 770 Re 760 Os 839 Ir 878 Pt 868 Au 890 Hg 1007 Tl 589 Pb 716 Bi 703 Po 812 At -- Fr -- Ra 509 y Ac 490 Rf -- Db -- Sg -- Bh -- Hs -- Mt -- Ds Uuu -- Uub Uut Uuq Uup He 2372 Ne 2081 Ar 1521 Kr 1351 Xe 1170 Rn 1038 Uuo * Lanthanide series y Actinide series Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

37 Periodic Trends Electronegativity Indicates the relative ability of atoms to attract electrons in a chemical bond In chemical bond, the atom with the greater electronegativity more strongly attracts the bonds electrons Increases as move left-to-right Decreases as move down a group Measured in units called Pauling's

38 Period Electronegativities 1A 8A 1 H 2A 3A 4A 5A 6A 7A Li Be B O F 2.5 C N Na Mg Al Si P S Cl B 4B 5B 6B 7B 8B 1B 2B K 0.8 Ca 1.0 Sc 1.3 Ti 1.5 V 1.6 Cr 1.6 Mn 1.5 Fe 1.8 Co 1.8 Ni 1.8 Cu 1.9 Zn 1.7 Ga 1.6 Ge 1.8 As 2.0 Se 2.4 Br 2.8 Rb 0.8 Sr 1.0 Y 1.2 Zr 1.4 Nb 1.6 Mo 1.8 Tc 1.9 Ru 2.2 Rh 2.2 Pd 2.2 Ag 1.9 Cd 1.7 In 1.7 Sn 1.8 Sb 1.9 Te 2.1 I 2.5 Cs 0.7 Ba 0.9 La * 1.1 Hf 1.3 Ta 1.5 W 1.7 Re 1.9 Os 2.2 Ir 2.2 Pt 2.2 Au 2.4 Hg 1.9 Tl 1.8 Pb 1.8 Bi 1.9 Po 2.0 At 2.2 y Fr Ra Ac * Lanthanides: y Actinides: Below

39 The arrows indicate the trend: Ionization energy and Electronegativity INCREASE in these directions

40 Melting Points H Li Na 98 K Be 1283 B 2027 He C N O F Ne Si P S Cl Ar Mg > 3000 o C o C Al Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Cs Ba 28.6 La Hf Mg 650 Symbol Melting point o C Nb 2487 Mo 2610 Tc 2127 Ru 2427 Rh 1966 Pd 1550 Ag 961 Cd 321 In Sn Sb Te 450 I Xe 2222 Ta 2997 W 3380 Re 3180 Os 2727 Ir 2454 Pt 1769 Au 1063 Hg Tl Pb Bi Po At Rn

41 Densities of Elements H Li 0.53 Na 0.97 K 0.86 Rb 1.53 Be 1.8 Mg Cs Ba Ca Sc 1.55 (2.5) Ti V Cr Mn Fe Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd La Hf B 2.5 C 2.26 N 0.81 He O F Ne Al Si P S Cl Ar w Co Ni Cu Zn Ga Ge As Se Br Kr , In 7.3 Sn 7.3 Sb 6.7 Te 6.1 I 4.93 Xe Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn g/cm g/cm 3 > 18.0 g/cm 3 Mg 1.74 Symbol Density in g/cm 3 C, for gases, in g/l

42 Nuclear charge increases Shielding increases Atomic radius increases Ionic size increases Ionization energy decreases Electronegativity decreases Summary of Periodic Trends Shielding is constant Atomic radius decreases Ionization energy increases Electronegativity increases Nuclear charge increases 1A 0 2A 3A 4A 5A 6A 7A Ionic size (cations) decreases Ionic size (anions) decreases

43 H 1 Li 3 Na 11 K 19 Rb Be 4 Ca Sc Ti V Sr Y Cs 39 Zr 23 Cr Ba Hf Ta * W Ra W Rf Fr Mg 12 Hydrogen Alkali metals Alkaline Earth Metals Coinage Metals Other Transition Elements Metalloids (B, Si, Ge, As, Sb, Te, At) B 5 C 6 N Al Si P O 15 S 8 F 16 Cl He 2 Ne 9 10 Ar Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 40 Nb 41 Mo 42 Tc 43 Ru 44 Rh 45 Pd 46 Ag 47 Cd 48 In 49 Sn 50 Sb 51 Te 52 I Xe Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Db Sg Bh Hs Mt Halogens Noble Gases Other Nonmetals Lanthanides Actinides Other metals * W La 57 Ac 89 Ce 58 Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr