Assertion and reason: filling orbitals

Exercise and reference answers

Questions

1. Reason

   Pauli forbids two electrons in an atom sharing all four quantum numbers.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   An orbital holds at most two electrons.

2. Reason

   Hund's rule of maximum multiplicity requires single occupancy first.

   Verdict

   Both are true; the reason explains the assertion.

   Assertion

   Electrons spread out before pairing up in a subshell.

3. Reason

   Rutherford discovered the nucleus by alpha-particle scattering.

   Verdict

   Both are true; the reason does not explain the assertion.

   Assertion

   Orbitals fill in order of increasing energy.

Explanation