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
. The value of this quantum number ranges from
. When l = 2, the value of
will be -2, -1, 0, +1, +2.
Spin Quantum number : It describes the direction of electron spin. This is represented as
The value of this is
for upward spin and
for downward spin.
As we are given that, ![n=3,l=1,m_l=1](/tpl/images/0258/1789/ad9e3.png)
So,
(For each sub-shell)
From this we conclude that,
that means there is one orbital that contains two electrons with opposite spin.
Hence, the number of electrons in an atom are, 2.