Pictorial Description of Lone Pairs

As we already noted, according to the QM theory, electrons occupy orbitals, which can be described as spatial objects, with certain volumes around the atom. An orbital represents the volume that encompasses the maximum probability of finding the electron around the atom. The lone-pair orbitals of main elements have the lobe 

SCHEME 7.R.1 Lobes of bonding orbitals (a) In methane, the lobes are oriented along the C—H bond axes, (b) In ethylene, one of the C—C bonds (the one with the shaded lobes, labeled as a it bond), lies above and below the molecular plane, (c) When the two CH2 units of ethylene are perpendicular to each other, the n bond is broken. 

---