Molecular orbital theorem

Valence Bond Theorem explains the formation of covalent bond within compound molecule. To form a covalent bond there may have different way of overlapping the electron clouds. What is the better way of forming covalent bond?  Molecular orbital theorem explains the better way of covalent bond formation. According to molecular orbital theory of formation of covalent bond, all of the atomic orbital forms a molecular orbital by combining and mixing. This new orbital structure is different from the atomic orbital structure. To form new molecular orbital all of the atomic orbitals distributed in a systematic pattern. The number of new formed molecular orbital is equal to the number of atomic orbital. The molecular orbital theorem constitutes with some basic features. Molecules are different from the its constituent atoms.
 Molecular orbital forms by combining of the atomic orbital of the atoms. The shapes of the molecular orbital is related on the shape of atomic orbitals. Molecular orbitals process definite energy levels. In molecular orbital theorem electrons are considered as the moving nature with the impacts of nuclei.