Which of the following combinations of orbtials are allowed in LCAO method (considering z-axis to be molecular axis) and sketch the shapes of molecular orbitals formed by their addition and subtraction:
(i)    s and p_z
(ii)    p_x and p_x
(iii)    p_z and p_y
(iv)    s and p_x.

Give the points of difference between sigma and pi molecular orbitals ?

What informations are conveyed from the electronic configuration of the molecule?

Define bond order. What informations are conveyed by bond order?

Give the number of electrons which occupy the bonding molecular orbital in H₂⁺ H₂ and He₂.   

What do you understand by bond order? How is it related with bond length and bond energy? Explain on the basis of bond order that He₂ molecule does not exist.

Why the bond orders of He₂⁺ and H₂^– are identical?

Using LCAO method for the formation of molecular orbitals in case of homonuclear diatomic hydrogen molecule.

Draw the molecular orbital diagram for:
(i) Be₂
(ii) B₂ and predict bond order and magnetic properties.