There 2 electrons in an atom can share the quantum numbers n=2, l=1 and ml=1. The correct answer between all the choices given is the last choice. I am hoping that this answer has satisfied your query about and it will be able to help you.
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 [tex]m_l[/tex]. The value of this quantum number ranges from [tex](-l\text{ to }+l)[/tex]. When l = 2, the value of [tex]m_l[/tex] will be -2, -1, 0, +1, +2.
Spin Quantum number : It describes the direction of electron spin. This is represented as [tex]m_s[/tex] The value of this is [tex]+\frac{1}{2}[/tex] for upward spin and [tex]-\frac{1}{2}[/tex] for downward spin.
As we are given that, [tex]n=3,l=1,m_l=1[/tex]
So,
[tex]m_s=+\frac{1}{2}\text{ and }-\frac{1}{2}[/tex] (For each sub-shell)
From this we conclude that, [tex]m_l=1[/tex] that means there is one orbital that contains two electrons with opposite spin.
Hence, the number of electrons in an atom are, 2.
