Answer : The number of electrons in an atom are, 2.
Explanation :
Principle Quantum Numbers : It describes the size of the orbital and the energy level. It is represented by n. Where, n = 1,2,3,4....
Azimuthal Quantum Number : It describes the shape of the orbital. It is represented as 'l'. The value of l ranges from 0 to (n-1). For l = 0,1,2,3... the orbitals are s, p, d, f...
Magnetic Quantum Number : It describes the orientation of the orbitals. It is represented as \(m_l\). The value of this quantum number ranges from \((-l\text{ to }+l)\). When l = 2, the value of \(m_l\) will be -2, -1, 0, +1, +2.
Spin Quantum number : It describes the direction of electron spin. This is represented as \(m_s\) The value of this is \(+\frac{1}{2}\) for upward spin and \(-\frac{1}{2}\) for downward spin.
As we are given that, \(n=3,l=1,m_l=1\)
So,
\(m_s=+\frac{1}{2}\text{ and }-\frac{1}{2}\) (For each sub-shell)
From this we conclude that, \(m_l=1\) that means there is one orbital that contains two electrons with opposite spin.
Hence, the number of electrons in an atom are, 2.
