Answer : The number of electrons in an atom is, 2 electrons
Explanation :
As we know that there are four quantum numbers which are principle quantum number, azimuthal quantum number, magnetic quantum number and spin magnetic quantum number.
The Principle quantum number, n = 3. That means the electron present in the third energy level.
The Azimuthal quantum number, l = 2. That means the electron present in the d sub-shell.
The magnetic quantum number, . That means it shows the 2 electrons present in one of the five 3d orbitals.
Hence, the number of electrons in an atom is, 2 electrons