Consider ground-state helium having two electrons in orbit. If one of the electrons has quantum numbers $\left( n , \ell l , m _ { 1 } , m _ { s } \right)$ of $1,0,0 , - 1 / 2$ respectively, the quantum numbers for the other electron will be
A) $1,0,0 , + 1 / 2$.
B) $1,1,0 , - 1 / 2$.
C) $1,1,1 , + 1 / 2$.
D) none of the given answers.

Question

Quizplus · Accepted Answer

In the ground state of helium, both electrons occupy the lowest energy level, which is the 1s orbital. This orbital is described by the quantum numbers $n=1$, $\ell=0$, and $m_\ell=0$. The only difference between the two electrons in a helium atom can be their spin quantum number, $m_s$, due to the Pauli exclusion principle. Since one electron has $m_s = -1/2$, the other must have $m_s = +1/2$, making option A correct.

Consider Ground-State Helium Having Two Electrons in Orbit (n,ℓl,m1,ms)\left( n , \ell l , m _ { 1 } , m _ { s } \right)(n,ℓl,m1​,ms​)

Consider Ground-State Helium Having Two Electrons in Orbit $\left( n , \ell l , m _ { 1 } , m _ { s } \right)$