Concept:The number of orbits in an atom equals the number of electron shells occupied by its electrons.
Explanation:An atom with atomic number
13 contains
13 electrons in its neutral state.
Electrons fill the shells in the order of increasing energy level.
The first shell can hold a maximum of
2 electrons, and the second shell can hold up to
8 electrons.
So, the electron configuration is
2,8,3.
These
13 electrons are distributed into three energy levels or shells.
The first shell contains
2 electrons, the second shell contains
8 electrons, and the third shell contains
3 electrons.
Therefore, the atom contains exactly
3 orbits.
Answer:3 orbits
Correct option: D