Chapter 8 Electron Configuration and Chemical Periodicity

Chapter 8 Electron Configuration and Chemical Periodicity -...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 8 Electron Configuration and Chemical Periodicity 8.1 Elements are listed in the periodic table in an ordered, systematic way that correlates with a periodicity of their chemical and physical properties. The theoretical basis for the table in terms of atomic number and electron configuration does not allow for an "unknown element" between Sn and Sb. 8.2 Today, the elements are listed in order of increasing atomic number. This makes a difference in the sequence of elements in only a few cases, as the larger atomic number usually has the larger atomic mass. One exception is iodine, Z = 53 with tellurium, Z = 52. 8.3 a) predicted AM(K) = amu 3 2 54. = 2 47 85. + 99 . 2 2 = 2 AM(Rb) + AM(Na) (actual value = 39.1) b) predicted MP(Br 2 ) = C 6.3 = 2 C 113.6 + C 101.0 = 2 ) I MP( + ) Cl MP( 2 2 ° ° ° - (actual value = - 7.2 ° C) 8.4 a) predicted BP(HBr) = C 60.2 = 2 C) 35.4 ( + C 84.9 = 2 BP(HI) + BP(HCl) ° - ° - ° - (actual value = - 67.0 ° C) b) predicted BP(AsH 3 ) = C 2 52. = 2 C) 17.1 ( + C 87.4 = 2 ) SbH BP( + ) PH BP( 3 3 ° - ° - ° - (actual value = - 55 ° C) 8.5 n : 1, 2, 3, 4. .. l : 0, 1, 2, . .. n - 1 m l : - l, ( - l + 1), . .. 0, . .. (l - 1), +l m s : ±½ 8.6 m s relates to just the electron; the others describe the orbital. 8.7 Within an atom, no two electrons may have the identical four quantum numbers. Within a particular orbital there can be only two electrons and they must have paired spins. 8.8 In a one-electron system, all sublevels of a particular level have the same energy. In many electron systems, the principal energy levels are split into sublevels of differing energies. This splitting is due to electron-electron repulsions. Be 3+ would be more like H since both have only one 1s electron. 8.9 Shielding occurs when inner-shell electrons protect or shield outer-shell electrons from the full attractive force of the nucleus. The effective nuclear charge is the nuclear charge an electron actually experiences. As the number of shielding electrons increases, the effective nuclear charge decreases. 154
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8.10 The penetration effect occurs when the probability distribution of an orbital is large near the nucleus, which results in an increase of the overall attraction of the nucleus for the electron, lowering its energy. Shielding results in lessening this effective nuclear charge on outer shell electrons, since they spend most of their time at distances farther from the nucleus and are shielded from the nuclear charge by the inner electrons. The lower the l quantum number of an orbital, the more time the electron spends penetrating near the nucleus. This results in a lower energy for a 3p electron than for a 3d electron in the same atom. 8.11
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/21/2010 for the course CHEM 1A taught by Professor Kobiashi during the Spring '07 term at Ventura College.

Page1 / 13

Chapter 8 Electron Configuration and Chemical Periodicity -...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online