What are the characteristics features of π-bond ?

(1) π-bond fired by lateral (sidewise) overlapping of atomic orbitals.

(2) lateral overlapping is only partial, so bonds formed are weaker and hence more reactive than sigma bond.

(3) Free rotation about a π- bond is not possible.

(4) π- bond is weaker than sigma bond.

(5) π-bonds are non directional, so do not determine the shape of a molecules.

(5) π- bond take part in resonance.

(6) π- bond formed by pure or anhybrid orbitals.

What is the difference between 2p and 3p orbitals?

Importance difference in between 2p and 3p Orbitals is their energy.

The energy of atomic orbitals depends upon principal as well as azimuthal quantum number, which is  more common known as (n+l) rule .
According to (n+l) rule the atomic orbital has less (n+l)  value also has less energy vice versa.
If the value of (l):is same for two different orbitals then the greater the value of n greater is energy and vice versa.
For 2p => n= 2, l=0,. =>n+l= 2+0=2
For 3p => n= 3, l=0,. =>n+l= 2+0=3
Hence 3p have more energy than 2p orbital