Hydrogen atom electronic structure

Methane (natural gas) is a gas whose molecules contain atoms of carbon and hydrogen. The electron structures are ... 

Suppose that we can make a guess at theJo7m of the orbitals which minimise eqn (2.1) and further suppose that this functional form of each of the approximate orbitals depends on a number of parameters. An obvious example is the case of the electronic structure of atoms which are all the same shape and there is a familiar model for the electronic structure the hydrogen atom. The parameters on which this model of atomic electronic structure might depend are the effective nuclear charges of each orbital i.e. replacing the hydrogenic Zjn by... 

Fluorine attracts electrons in a covalent bond much more than hydrogen - it has a high electronegativity. Because the shared electrons are more associated with the fluorine atom rather than the hydrogen atom, the structural formula of the molecule is sometimes written as H8+—F -... 

All these structures 87-90, inclusive) give each of the four ruthenium atoms the favored 18-electron rare gas configuration. Since the primary question concerning the structures of the isomers of H2Ruij(CO)i3 and HitRui+(CO) 12 is the location of the hydrogen atoms, these structures will remain somewhat uncertain until neutron-diffraction studies become available. However,... 

One of our goals in this chapter has been to determine the electronic structures of atoms. So far we have seen that quantum mechanics leads to a very elegant description of the hydrogen atom. The hydrogen atom, however, has only one electron. How must our description of atomic electronic structure change when we consider atoms with two or mote electrons (a inany-electrcm atom) To describe these atoms, we must consider not only the nature of orbitals and their relative energies but also how the electrons populate the available orbitals. 

Methanal (CH2O) has an sp -hybridized oxygen atom. The sp lone pair electrons he in the same plane as the carbon and hydrogen atoms. Methanal structurally resembles ethene. 

The carbon atom has a share in eight electrons (Ne structure) whilst each hydrogen atom has a share in two electrons (He structure). This is a gross simplification of covalent bonding, since the actual electrons are present in molecular orbitals which occupy the whole space around the five atoms of the molecule. 

The hydrogen atom and one-electron ions are the simplest systems in the sense that, having only one electron, there are no inter-electron repulsions. However, this unique property leads to degeneracies, or near-degeneracies, which are absent in all other atoms and ions. The result is that the spectrum of the hydrogen atom, although very simple in its coarse structure (Figure 1.1) is more unusual in its fine structure than those of polyelectronic atoms. For this reason we shall defer a discussion of its spectrum to the next section. 

Note that these compounds are covalently bonded compounds containing only hydrogen and carbon. The differences in their strucmral formulas are apparent the alkanes have only single bonds in their structural formulas, while the alkenes have one (and only one) double bond in their structural formulas. There are different numbers of hydrogen atoms in the two analogous series. This difference is due to the octet rule that carbon must satisfy. Since one pair of carbon atoms shares a double bond, this fact reduces the number of electrons the carbons need (collectively) by two, so there are two fewer hydrogen atoms in the alkene than in the corresponding alkane. 

The concept of chemical periodicity is central to the study of inorganic chemistry. No other generalization rivals the periodic table of the elements in its ability to systematize and rationalize known chemical facts or to predict new ones and suggest fruitful areas for further study. Chemical periodicity and the periodic table now find their natural interpretation in the detailed electronic structure of the atom indeed, they played a major role at the turn of the century in elucidating the mysterious phenomena of radioactivity and the quantum effects which led ultimately to Bohr s theory of the hydrogen atom. Because of this central position it is perhaps not surprising that innumerable articles and books have been written on the subject since the seminal papers by Mendeleev in 1869, and some 700 forms of the periodic table (classified into 146 different types or subtypes) have been proposed. A brief historical survey of these developments is summarized in the Panel opposite. 

From electronic structure theory it is known that the repulsion is due to overlap of the electronic wave functions, and furthermore that the electron density falls off approximately exponentially with the distance from the nucleus (the exact wave function for the hydrogen atom is an exponential function). There is therefore some justification for choosing the repulsive part as an exponential function. The general form of the Exponential - R Ey w function, also known as a ""Buckingham " or ""Hill" type potential is... 

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