Chemistry answers and questions

  1.What is effective atomic number rule(EAN)? 2.Comparison of effective atomic number rule and 18 electron rule. 3.Limitations of EAN Rule. Effective atomic number Effective atomic number rule was put for forward by Sidgwick and Bailey . It is observed by transition metal carbonyls which shows diamagnetic behavior. The composition of stable binary metal carbonyls is largely predictable by EAN rule. The effective atomic number rule predicts that metal in zero or low oxidation state will gain electrons from sufficient number of ligands so that metal will achieve the electronic configuration of next noble gas. Counting Rules 1.   Count two electrons for each CO. 2. Count one electron for each metal-metal bond. 3. Find the number of electrons that formally belong to the metal atom alone by (a) adding up the charges on the ligands and changing the sign ,(b) finding the metal oxidation number by adding this number to the total charge on the complex, and (c) sub...

         What is Slater's Rule and its significance? How to calculate value of σ  and Zeff using Slater' Rule: Slater's Rule : Slater’s rules are a set of empirical guidelines used to calculate the shielding constant (σ) and the effective nuclear charge (Zeff) experienced by an electron in a multi-electron atom. They were introduced by John C. Slater to simplify the complex quantum mechanical interactions between electrons. These rules estimate how much the inner electrons reduce the attractive force of the nucleus on outer electrons. Mathematically:                              Zeff=Z−S where: Z = atomic number (total nuclear charge)             S = shielding constant (calculated using Slater’s rules Significance of Slater's Rule: To quanti...

What is Paramagnetic, Diamagnetic, Ferromagnetic, Antiferromagnetic and Ferrimagnetic behavior of substances? What is the effect of temperature on these properties? Paramagnetic substances: These substances are attracted by the magnetic field and have unpaired electrons. These lose magnetism in the absence of magnetic field. Some examples of paramagnetic substances are transition metals like Cr, Mn, Co, Fe and metal oxides like CuO,VO 2 . Diamagnetic substances: These substances are weakly repelled by magnetic field and have no unpaired electrons. Some examples of diamagnetic substances are H 2 O, benzene, NaCl, TiO 2 . Ferromagnetic substances: Such substances are strongly attracted by magnetic field. In the absence of magnetic field magnetic field these substances have magnetic domains randomly oriented in such a way that their overall magnetic moment gets cancelled. But in the presence of magnetic field they are oriented in such a way that they together produce a str...