Topic 3 - Periodicity 3.1 – Periodic Table .1

Periodic Table .2

The Periodic Table-Key Questions What is the periodic table ? What information does the table provide ? How can one use the periodic table to predict the properties of the elements? .3

Periodic Table The development of the periodic table brought a system of order to what was otherwise an collection of thousands of pieces of information. The periodic table is a milestone in the development of modern chemistry. It not only brought order to the elements but it also enabled scientists. to predict the existence of elements that had not yet been discovered . .4

Early Attempts to Classify Elements Dobreiner’s Triads (1827) Classified elements in sets of three having similar properties. Found that the properties of the middle element were approximately an average of the other two elements in the triad. .5

Dobreiner’s Triads Element Atomic Mass Average Density Cl Br I 35.5 (amu) Average Density (g cm-3) Cl Br I 35.5 79.9 126.9 81.2 1.56 3.12 4.95 3.25 Ca Sr Ba 40.1 87.6 137.3 88.7 1.55 2.6 3.5 2.53 Note: In each case, the numerical values for the atomic mass and density of the middle element are close to the averages of the other two elements .6

Newland’s Octaves -1863 John Newland attempted to classify the then 62 known elements of his day. He observed that when classified according to atomic mass, similar properties appeared to repeat for about every eighth element His Attempt to correlate the properties of elements with musical scales subjected him to ridicule. In the end his work was acknowledged and he was vindicated with the award of the Davy Medal in 1887 for his work. .7

Dmitri Mendeleev Dmitri Mendeleev is credited with creating the modern periodic table of the elements. He gets the credit because he not only arranged the atoms, but he also made predictions based on his arrangements His predictions were later shown to be quite accurate. .8

Mendeleev’s Periodic Table Mendeleev organized all of the elements into one comprehensive table. Elements were arranged in order of increasing mass. Elements with similar properties were placed in the same row. .9

Mendeleev’s Periodic Table .1010

Mendeleev’s Periodic Table Mendeleev left some blank spaces in his periodic table. At the time the elements gallium and germanium were not known. He predicted their discovery and estimated their properties. .11

The Modern Periodic Table The Periodic Table has undergone several modifications before it evolved in its present form. The current form is usually attributed to Glenn Seaborg in 1945. .12

Periodic Table Expanded View The Periodic Table can be arranged by energy sub levels The s-block is Group IA and & IIA, the p-block is Group IIIA - VIIIA. The d-block is the transition metals, and the f-block are the Lanthanides and Actinide metals The way the periodic table usually shown is a compressed view. The Lanthanides and actinides (F block) are cut out and placed at the bottom of the table. .13

Periodic Table Layout of the Periodic Table: Metals vs. nonmetals . Nonmetals Metals .14

The Three Broad Classes are the Representative, Transition, & Rare Earth Main (Representative), Transition metals, lanthanides and actinides (rare earth) .15

Additional Groupings in the Periodic Table Nonmetals, Metals, Metalloids, Noble gases .16

Periodic Table Electron configurations are inherent in the periodic table. H 1s1 He 1s2 B 2p1 Li 2s1 Be 2s2 B 2p1 C 2p2 N 2p3 O 2p4 F 2p5 Ne 2p6 Na 3s1 Mg 3s2 Al 3p1 Si 3p2 P 3p3 S 3p4 Cl 3p5 Ar 3p6 K 4s1 Ca 4s2 Sc 3d1 Ti 3d2 V 3d3 Cr 4s13d5 Mn 3d5 Fe 3d6 Co 3d7 Ni 3d8 Cu 4s13d10 Zn 3d10 Ga 4p1 Ge 4p2 As 4p3 Se 4p4 Be 4p5 Kr 4p6 Rb 5s1 Sr 5s2 Y 4d1 Zr 4d2 Nb 4d3 Mo 5s14d5 Tc 4d5 Ru 4d6 Rh 4d7 Ni 4d8 Ag 5s14d10 Cd 4d10 In 5p1 Sn 5p2 Sb 5p3 Te 5p4 I 5p5 Xe 5p6 Cs 6s1 Ba 6s2 La 5d1 Hf 5d2 Ta 5d3 W 6s15d5 Re 5d5 Os 5d6 Ir 5d7 Ni 5d8 Au 6s15d10 Hg 5d10 Tl 6p1 Pb 6p2 Bi 6p3 Po 6p4 At 6p5 Rn 6p6 Fr 7s1 Ra 7s2 Ac 6d1 Rf 6d2 Db 6d3 Sg 7s16d5 Bh 6d5 Hs 6d6 Mt 6d7 .17

Periodic Table: Groups or Families Vertical columns in the periodic table are known as groups or families. The elements in a group have similar electron configurations. .18

Periodic Table: Periods Horizontal Rows in the periodic table are known as Periods The Elements in a period undergo a gradual change in properties as one proceeds from left to right .19

Alternate Periodic Tables Although we are most familiar with the periodic table that Seaborg proposed more than 60 years ago, several alternate designs have been proposed. .20

Alternate Periodic Tables .21

Alternate Periodic Tables II .22

Alternate Periodic Tables III .23

Alternate Periodic Tables IV