Periodic Table Elements (original) (raw)

How do chemical properties of the atoms change under pressure

2015

Abundant evidence has shown the emergence of dramatic new chemical phenomena under pressure, including the formation of unexpected crystal structures and completely new counterintuitive compounds. In many cases, there is no convincing explanation for these phenomena and there are virtually no chemical rules or models capable of predicting or even rationalizing these phenomena. Here we consider two central chemical properties of atoms, electronegativity and chemical hardness, and determine them as a function of pressure up to 500 GPa. For elements without orbital transfer at high pressure, electronegativity first increases and then decreases, while chemical hardness monotonically decreases as pressure increases. For some active metals, the chemical hardness has a further increase at pressures of the order of tens-hundreds of gigapascals. Furthermore, we discover that orbital transfer, in particular s-d transfer, makes Ni a "pseudo-noble-gas", Fe and Co strong electron acceptors, while Cu and Zn become active metals. We show the explicative and predictive power of our electronegativity and chemical hardness scales under pressure.

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ELECTRONEGATIVITY: EXPECTATION VALUE OF POWER OF AN ATOM IN A MOLECULE.

International Journal of Advanced Research (IJAR), 2019

Advancing theory of electronegativity , new approach is established by the study of binding (or bonding) state in between two homo- atoms or hetero- atoms. Electronegativity is a confused as it is sandwiched among three entities such as i) energy ii) force iii) Charge. This paper interprets that Electronegativity (χ) is the expectation value of attracting or holding power of electron an atom in either of homo-atomic or hetro-atomic system. This value has been described in terms of von Neuman -minimax theorem: χ(maxA . min B) =χ (min A. max B) where max A and max B stands for atom?s maximum ability and min A and min B stands for atom?s minimum ability . Three structures(i)AB(Covalent structure) ;mini-max theorem,(ii)A+B-(ionic structure);right-side of mini-max theorem, (iii)A-B+(ionic structure);left-side of theorem for giving mathematical formulation electronegativity are established.Hellmann-Feynman force as an expectation value for electronegativity is established.

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Periodic Table Elements (original) (raw)

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