Covalent Bonding in H2 and

A covalent bond occurs when two atoms share two or more electrons. More specifically, in the context of molecular orbital theory, a single covalent bond between two atoms occurs when two electrons (one from each of the atoms) occupies a bonding molecular orbital. Other terms 

Reaction 3.2 is a prime example of the use of the terms Lewis acid and Lewis base. G. N. Lewis suggested the usage such that a donor of an electron pair is a base and the acceptor molecule is an acid. The classical Bransted acid and base pair, H+(aqueous) and OH (aqueous), are encompassed by the Lewis definitions as they combine to give water, the hydroxide ion supplying both electrons. 

The meanings of the terms bonding non-bonding and anti-bonding orbitals are 

Equations 3.3 and 3.4 seem to imply that both atomic wave functions j/A and contribute fully (100%) to both molecular wave functions 0, and 02 The impossibility of this is taken care of in the section on normalization For the purposes of this section, normalization may be ignored as it does not alter the symmetry properties of the molecular wave functions. 

The H7+ molecule-ion, which consists of two protons and one electron, represents an even simpler case of a covalent bond, in which only one electron is shared between the two nuclei. Even so, it represents a quantum mechanical three-body problem, which means that solutions of the wave equation must be obtained by iterative methods. The molecular orbitals derived from the combination of two Is atomic orbitals serve to describe the electronic configurations of the four species H2+, H2, He2+ and He2. 

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