Non-planar Molecules:
This simply means that the atoms do not all lie in one plane - the molecule is "3-dimensional".
We will consider the examples:
(a) Chloromethane
(b) Methane
(c) Allene
(a) Chloromethane - ClCH3
(b) Methane - CH4
(c) Allene - H2C=C=CH2