Question

When there are two electrons in the 3s sublevel, they :

• A. must occupy different orbitals
• B. Heisenberg uncertainty principle predicts that they must periodically jump to the 3p sublevel
• C. the oxidation state of the atom must be 2+
• D. must have opposite spins
• E. are oppositely charged

Answer 1

Answer: (D)

must have opposite spins

When there are two electrons in the 3s sublevel, they must have opposite spins.
This is in accordance with Pauli's exclusion principle which states that, "only two electrons may exist in the same orbital with three quantum numbers same, i.e. the fourth quantum number different and these electrons must have opposite spins."