Atomic weights Ionization

Electronic configuration Atomic munher Atomic weight Ionization potential (eV)... 

Enache et al. (2000) QCARs and Enache et al. (2003) QCAR for predicting cation toxicity using atomic number, atomic weight, ionization potential differential and standard reduction-oxidation potential... 

Atomic number Element symbol Atomic weight Ionization potentials (eV) First Second ... 

In order to successfully interpret a mass spectrum, we have to know about the isotopic masses and their relation to the atomic weights of the elements, about isotopic abundances and the isotopic patterns resulting therefrom and finally, about high-resolution and accurate mass measurements. These issues are closely related to each other, offer a wealth of analytical information, and are valid for any type of mass spectrometer and any ionization method employed. (The kinetic aspect of isotopic substitution are discussed in Chap. 2.9.)... 

Symbol Ar atomic number 18 atomic weight 39.948 an inert gas element electronic configuration Is22s22p63s23p ionization potential 15.76eV stable isotopes and natural abundance Ar-40 99.6%, Ar-36 0.337%, Ar-38 0.063% unstable isotopes, half-life and disintegration mode ... 

Symbol Ba atomic number 56 atomic weight 137.327 a Group llA (Group 2) alkaline earth element electronic configuration [Xejs valence state +2 ionic radius of Ba2+ in crystal (corresponding to coordination number 8) 1.42 A first ionization potential lO.OOeV stable isotopes and their percent abundances Ba-138 (71.70), Ba-137 (11.23), Ba-136 (7.85), Ba-135 (6.59), Ba-134 (2.42) minor isotopes Ba-130 (0.106) and Ba-132 (0.101) also twenty-two radioisotopes are known. 

Symbol Be atomic number 4 atomic weight 9.012 a Group IIA (Group 2) metal the lightest alkaline-earth metallic element atomic radius l.OOA ionic radius (Be2+) 0.30A electronic configuration Is22s2 ionization potential, Be 9.32eV, Be + 18.21 eV oxidation state +2... 

Symbol Cd atomic number 48 atomic weight 112.41 a Group IIB (Group 12) metallic element ionization potential 8.994eV electron configuration [Kr]4di°5s2 valence state +2 standard electrode potential, E° -0.40V. The isotopes and their natural relative abundance are ... 

Symbol Cs atomic number 55 atomic weight 132.905 a Group lA (Group 1) alkali metal element electron configuration [Xe]6si atomic radius 2.65 A ionic radius (Cs ) 1.84 A ionization potential 3.89 eV valence +1 natural isotope Cs-133 37 artificial isotopes ranging in mass numbers from 112 to 148 and half-lives 17 microseconds (Cs-113) to 2.3x10 years (Cs-135). 

Symbol Kr atomic number 36 atomic weight 83.80 a Group 0 (Group 18) element inert gas element electron configuration Is22s22p63s23p 3di°4s24p valence state 0 an uncommon valence state +2 exists for its difluoride first ionization potential 13.999 volt six stable natural isotopes are known most abundant isotope Kr-84. Natural isotopes and their abundances Kr-78 (0.354%), Kr-80 (2.20%), Kr-82 (11.56%), Kr-83 (11.55%), Kr-84 (56.90%), Kr-86 (17.37%). 

Symbol Mg atomic number 12 atomic weight 24.305 a Group II A (Group 2) alkaline-earth metal atomic radius 1.60A ionic radius (Mg2+) 0.72A atomic volume 14.0 cm /mol electron configuration [Ne]3s2 valence +2 ionization potential 7.646 and 15.035eV for Mg+ and Mg2+, respectively three natural isotopes Mg-24(78.99%), Mg-25(10.00%), Mg-26(11.01%). 

Symbol Nd atomic number 60 atomic weight 144.24 a rare earth lanthanide element a hght rare earth metal of cerium group an inner transition metal characterized by partially filled 4/ subshell electron configuration [Xe]4/35di6s2 most common valence state -i-3 other oxidation state +2 standard electrode potential, Nd + -i- 3e -2.323 V atomic radius 1.821 A (for CN 12) ionic radius, Nd + 0.995A atomic volume 20.60 cc/mol ionization potential 6.31 eV seven stable isotopes Nd-142 (27.13%), Nd-143 (12.20%), Nd-144 (23.87%), Nd-145 (8.29%), Nd-146 (17.18%), Nd-148 (5.72%), Nd-150 (5.60%) twenty-three radioisotopes are known in the mass range 127-141, 147, 149, 151-156. 

Symbol Rb atomic number 37 atomic weight 85.468 a Group I (Group 1) alkali metal element electron configuration [Kr] 5si valence -i-l atomic radius 2.43A ionic radius, Rb+ 1.48A atomic volume 55.9 cc/g-atom at 20°C ionization potential 4.177 V standard electrode potential Rb+ + e Rb, E° = -2.98V two naturally-occurring isotopes, Rb-85 (72.165%) and Rb-87 (27.835%) Rb-87 radioactive, a beta emitter with a half-bfe 4.88xl0i° year twenty-seven artificial radioactive isotopes in the mass range 74—84, 86, 88-102. 

Symbol Na atomic number 11 atomic weight 22.9898 a Group lA (Group 1) alkali metal element electron configuration [NejSs valence +1 atomic radius 1.85A ionic radius, Na" in crystals 1.02A (for a coordination number 6) ionization potential 5.139 eV standard electrode potential, E°(Na+ + e Na) -2.71 V one naturally-occurring stable isotope, Na-23 (100%) sixteen artificial radioactive isotopes in the mass range 19-22, 24—35 longest-lived radioisotope, Na-22, ti/2 2.605 year shortest-lived isotope Na-35, ti/2 1.5 ms. 

Another set of units is milliequivalents per liter. Milligrams per liter can be converted to milliequivalents per liter by dividing by the equivalent weight. For ionization reactions, equivalent weight is obtained by dividing the atomic weight of the ion by its valence. 

For example, equivalent weight of HC1 is 36.45/1, or 36.45, H2S04 is 98/2 or 49, or CH3COOH is 60/1 or 60. In acetic acid, CH3COOH, although there are totally 5 H atoms, the acid has only one dissociable H atom which ionizes in water as follows ... 

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