Moore's law of components, "a component being a transistor, resistor, diode or capacitor", at minimum cost. Transistors per integrated circuit – The most popular formulation is of the doubling of the number of transistors on integrated circuits every two years. At the end of the 1970s, Moore's law became known as the limit for the number of transistors on the most complex chips. The graph at the top shows this trend holds true today. Density at minimum cost per transistor – This is the formulation given in Moore's 1965 paper. It is not just about the density of transistors that can be
18-electron rule have achieved the same electron configuration as the noble gas in the period. The rule and its exceptions are similar to the application of the octet rule to main group elements. The rule is not helpful for complexes of metals that are not transition metals, and "interesting or useful transition metal complexes will violate the rule" because of the consequences deviating from the rule bears on reactivity. The rule was first proposed by American chemist Irving Langmuir in 1921. The rule usefully predicts the formulae for low-spin complexes of the Cr, Mn, Fe, and Co triads. Well-known examples include ferrocene,