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reader8 - Petrucci 9.1 Trends in the Periodic Table • We...

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Unformatted text preview: Petrucci 9.1 Trends in the Periodic Table • We can predict a lot about the chemistry and properties of an element by its location in the periodic table • Periodic table was discovered before the knowledge about electron config- urations – Mendeleev’s Periodic Table from 1869: Row Group I Group II Group III Group IV Group V Group VI Group VII Group VIII — — — RH 4 RH 3 RH 2 RH — R 2 O RO R 2 O 3 RO 2 R 2 O 5 RO 3 R 2 O 7 RO 4 1 H=1 2 Li=7 Be=9.4 B=11 C=12 N=14 O=16 F=19 3 Na=23 Mg=24 Al = 27.3 Si=28 P=31 S=32 Cl=35.5 4 K= 39 Ca=40 Sc = 44 Ti=48 V= 51 Cr=52 Mn=55 Fe, Co, Ni, Cu 5 (Cu = 63) Zn=65 Ga = 68 –=72 As= 75 Se=78 Br=80 6 Rb= 85 Sr=87 ?Yt = 88 Zr=90 Nb= 94 Mo=96 Tc =100 Ru, Rh, Pd, Ag 7 (Ag=108) Cd= 112 In= 113 Sn= 118 Sb=122 Te=125 I=127 8 Cs= 133 Ba=137 ?Di = 138 ?Ce=140 – – – –, –, –, – 9 (–) – – – – – – 10 – – ?Er=178 ?La=180 Ta=182 W=184 – Os, Ir, Pt, Au 11 (Au=199) Hg=200 Tl=204 Pb=207 Bi=208 – – 12 – – – Th=231 – U=240 – –, –, –, – Petrucci 9.2 Origin of Periodic Trends • Valence electron configuration dictates chemistry H Li Na K Rb Cs 1 s 1 [He] 2 s 1 [Ne] 3 s 1 [Ar] 4 s 1 [Kr] 5 s 1 [Xe] 6 s 1 Be Mg Ca Sr Ba Ra [He] 2 s 2 [Ne] 3 s 2 [Ar] 4 s 2 [Kr] 5 s 2 [Xe] 6 s 2 [Rn] 7 s 2 • Mainly partly filled sub shells in valence band are important B Al Ga In [He] 2 s 2 2 p 1 [Ne] 3 s 2 3 p 1 [Ar] 4 s 2 3 d 10 4 p 1 [Kr] 5 s 2 4 d 10 5 p 1 Segments of the Periodic Table • Noble Gases – Has no partly filled orbitals • Main-Group Elements – Partly filled s or p orbitals • Transition Metals – Partly filled d orbitals • Lanthanides and Actinides – Partly filled f orbitals Ion Formation • Elements that are only one or two electrons off a noble gas configuration tends to form ions that has a noble gas electron configuration – Main group metals * Group 1 (Alkali metals) Na([Ne]3 s 1 )-→ Na + ([Ne]) + e- * Group 2 (Alkaline earth metals) Mg([Ne]3 s 2 )-→ Mg 2+ ([Ne]) + 2 e- – Main group non-metals * Group 16 (oxygen family) S([Ne]3 s 2 3 p 4 ) + 2 e--→ S 2- ([Ar]) * Group 17 (Halogens) Cl([Ne]3 s 2 3 p 5 ) + e--→ Cl- ([Ar]) Transition Metal Ions • Transition metal ions a special because they loose their s electrons before their d electrons – All first row TMs except Sc forms +2 ion Fe([Ar]4 s 2 3 d 6 )-→ Fe 2+ ([Ar]3 d 6 ) + 2 e- • 3 d electrons are shielded by 4 s electrons • No 4 s electrons means higher ef- fective charge for 3 d electrons • Lower energy 2 Ions With "‘Pseudo Noble Gas"’ Electron Configurations...
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reader8 - Petrucci 9.1 Trends in the Periodic Table • We...

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