Long Answer TypeDefine moleuclar orbital. What are the salient features of Molecular orbital theory?
Short Answer TypeLong Answer TypeWhat is a linear combination of atomic orbitals (LCAO) far obtaining molecular orbitals ?
Write the important conditions required for the linear combination of atomic orbitals to form molecular orbitals.
The following are the conditions for the linear combination of atomic orbitals:
(i) The combining atomic orbitals should have comparable energies.
(ii) The combining atomic orbitals must have proper orientations (same symmetry) so that they are able to overlap to a considerable extent. For example, assuming 2-axis as molecular (or internuclear axis), allowed the combination of atomic orbitals are 2pz orbital of one atom can combine with 2pz orbital of another atom. On the other hand, 2pz orbital of one atom cannot combine with 2px or 2py orbital of another atom or 2px can not combine with 2py. Similarly, 2s orbital of one atom can combine with 2pz orbital but cannot combine with 2lpx or 2py orbital of another atom because they do not have proper orientation for the overlap.
(iii) The extent of overlapping should be large. Greater the overlap, greater will be the electron density.
Short Answer TypeAssuming Z-axis as molecular (or internuclear) axis, label the molecular orbtials formed by the following combinations of atomic orbitals: (i) 1 s + 1 s (ii) 2py – 2pv (iii) 2Pz – 2pz.
Long Answer TypeDiscuss the shapes of molecular orbitals formed by the combination of the following atomic orbitals. (lateral overlap)
(i)2px + 2py (ii) 2pz – 2pz
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