The p-orbital set is made up of three subsets that are often referred to as Px, Py and Pz, depending on the axis. The different colours have been used simply to differentiate the different sub-p-orbitals when they come together (as depicted further down); they are otherwise the same as each other.
P-orbitals are often described as being like a barbell or dumb-bell in shape. This is because, as you can see above, there are two larger outer lobes to each sub-set.
Number of Electrons in a P-orbital
Each sub-p-orbital can hold two electrons i.e. Px can hold 2 electrons, Py can hold 2 electrons and Pz can hold 2 electrons. This means that in total, one set of p-orbitals can hold 6 electrons.
P-orbitals in Each Shell
Only two shells' p-orbitals have been depicted below: n=2 shell (2P orbitals), and n=3 shell (3P orbitals). There are however, also p-orbitals in other shells (e.g. n=4, n=5). Like s-orbitals, the p-orbitals also increase in diameter with each shell. This is because the electrons in sub-orbitals closer to the nucleus repel those electrons in the outer sub-orbitals.
| 2P orbitals