Answer: The atoms which belong to the same element are atom 2 and atom 5.
Step-by-step explanation:
Elements are identified by their atomic numbers.
Atomic number is defined as the number of protons or number of electrons that are present in an element.
Atomic number = Number of protons = Number of electrons
Two atoms having same number of protons will belong to same element.
From the given image, atom 2 and atom 5 have same number of protons which are 11.
Thus, both the atoms belong to same element.
Hence, the correct answer is atom 2 and atom 5.