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Mendeleev had predicted an atomic mass of 100 for eka-manganese in 1871, and the most stable isotopes of technetium are 97 Tc and 98 Tc. [ 5 ] Germanium was isolated in 1886 and provided the best confirmation of the theory up to that time, due to its contrasting more clearly with its neighboring elements than the two previously confirmed ...
The Avogadro constant, commonly denoted N A [1] or L, [2] is an SI defining constant with an exact value of 6.022 140 76 × 10 23 mol −1 (reciprocal moles). [3] [4] It is this defined number of constituent particles (usually molecules, atoms, ions, or ion pairs—in general, entities) per mole and used as a normalization factor in relating the amount of substance, n(X), in a sample of a ...
The God Equation: The Quest for a Theory of Everything is a popular science book by the futurist and physicist Michio Kaku. The book was initially published on April 6, 2021, by Doubleday. [1] [2] The book debuted at number six on The New York Times nonfiction best-seller list for the week ending April 10, 2021. [3]
Pauling's second rule is that the value of the first pK a for acids of the formula XO m (OH) n depends primarily on the number of oxo groups m, and is approximately independent of the number of hydroxy groups n, and also of the central atom X. Approximate values of pK a are 8 for m = 0, 2 for m = 1, −3 for m = 2 and < −10 for m = 3. [28]
Most notably, in a 1929 paper he set out an argument based on the Pauli exclusion principle and the Dirac equation that fixed the value of the reciprocal of the fine-structure constant as 𝛼 −1 = 16 + 1 / 2 × 16 × (16–1) = 136. When its value was discovered to be closer to 137, he changed his argument to match that value.
A more elaborate version was given by Gottfried Leibniz in the early eighteenth century. [1] Kurt Gödel created a formalization of Leibniz' version, known as Gödel's ontological proof. [1] A more recent argument was made by Stephen D. Unwin in 2003, who suggested the use of Bayesian probability to estimate the probability of God's existence. [2]
For Rutherford's alpha particle scattering from gold, with mass of 197, the reduced mass is very close to the mass of the alpha particle: = + = For lighter aluminium, with mass 27, the effect is greater: = + = a 13% difference in mass. Rutherford notes this difference and suggests experiments be performed with lighter atoms.
The buffering region is dependent upon the pKa, and is typically +/- 1.0 pH units of the pKa. The pKa of KHP is 5.4, so its pH buffering range would be 4.4 to 6.4; however, due to the presence of the second acidic group that bears the potassium ion, the first pKa also contributes to the buffering range well below pH 4.0, which is why KHP is a ...