Question

Please can someone explain the different kind of bonding in alkane alkene and alkyne?

Answer 1

Covalent bonds are conceived to be regions of high electron density, to which positively charged nuclei may be attracted such that nuclear-nuclear repulsion is negated and a net attractive force results.

Explanation:

We conceive of a sigma bond as a region of high electron density between 2 positively charged nuclei. `pi` bonds are regions of electron density above and below the nucleus-nucleus vector: that is there is no electron density between the nuclei, but interaction between the nuclei and the electron cloud lying above the nucleus-nucleus vector.

Try this link for one of Ernest's descriptions.