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In chemistry, the whole number rule states that the masses of the isotopes are whole number multiples of the mass of the hydrogen atom. [1] The rule is a modified version of Prout's hypothesis proposed in 1815, to the effect that atomic weights are multiples of the weight of the hydrogen atom. [ 2 ]
A mnemonic is a memory aid used to improve long-term memory and make the process of consolidation easier. Many chemistry aspects, rules, names of compounds, sequences of elements, their reactivity, etc., can be easily and efficiently memorized with the help of mnemonics.
Lipinski's rule of five, also known as Pfizer's rule of five or simply the rule of five (RO5), is a rule of thumb to evaluate druglikeness or determine if a chemical compound with a certain pharmacological or biological activity has chemical properties and physical properties that would likely make it an orally active drug in humans.
1302-42-7 AlO: aluminium monoxide: 14457-64-8 AlOSi: aluminium silicon monoxide: 37361-47-0 AlO 2: aluminium(IV) oxide: 11092-32-3 AlP: aluminium monophosphide: 20859-73-8 AlPO 4: aluminium phosphate: 7784-30-7 AlTe: aluminium monotelluride: 23330-86-1 AlTe 2: monoaluminium ditelluride: 39297-18-2 Al 2 BeO 4: beryllium aluminium oxide: 12004-06 ...
In analogy to the rule of five, it has been proposed that ideal fragments should follow the 'rule of three' (molecular weight < 300, ClogP < 3, the number of hydrogen bond donors and acceptors each should be < 3 and the number of rotatable bonds should be < 3). [4]
Shoolery's rule, which is named after James Nelson Shoolery, is a good approximation of the chemical shift δ of methylene groups in proton nuclear magnetic resonance. We can calculate shift of the CH 2 protons in a A–CH 2 –B structure using the formula
The Geneva Rules are the rules established by the International Chemistry Committee in 1892. These rules were the beginning of international cooperation for organic chemistry nomenclature . [ 1 ] They were decided upon by a group of 34 of leading chemists from 9 different European nations.
Because the S 2− anion has a subscript of 2 in the formula (giving a 4− charge), the compound must be balanced with a 4+ charge on the Pb cation (lead can form cations with a 4+ or a 2+ charge). Thus, the compound is made of one Pb 4+ cation to every two S 2− anions, the compound is balanced, and its name is written as lead(IV) sulfide .