Final answer:
The difference between a 2px and 3py orbital is their energy levels; 2px is in the second while 3py is in the third level. Both have a d_umbbell shape but the 3py orbital is larger.
Step-by-step explanation:
The difference between a 2px and a 3py orbital is that they belong to different subshells. These orbitals describe regions in space where there's a high probability of finding electrons. The 2px orbital is located in the second energy level ('2' denotes the principal quantum number) and the 'p' indicates the subshell type, which has d_umbbell-shaped orbitals. It is oriented along the x-axis, as indicated by the subscript 'x'. Similarly, the 3py orbital is in the third energy level and is oriented along the y-axis. Although both are 'p' orbitals, the number 2 or 3 indicates that they are part of different energy levels which affects their size and energy. Their shapes are essentially the same but the 3py orbital is larger due to its higher principal quantum number.