In an atom, the number of protons is equal to the atomic number, which determines the identity of the element. The number of neutrons can vary within an element, resulting in different isotopes. However, if an atom's mass is equal to its relative atomic mass (atomic weight), it implies that the atom has no neutrons and is an isotope with a mass number equal to the atomic number.
Therefore, the atom will have:
- Number of protons (equal to the atomic number)
- Number of neutrons (zero)
- Number of electrons (equal to the number of protons)
It's important to note that such an atom would be highly unstable, as the absence of neutrons typically leads to an imbalance in the atomic nucleus. Most elements have multiple stable isotopes with different numbers of neutrons.