Identify the rule (aufbau principle, Hund's rule, Pauli-Exclusion principle) violated by the following electron configurations.
i) Li     1s² 2p¹
ii) O    [He] 2s² 2p ↿↿  ↿   ↿ 
iii) P    [Ne] 3s² 3p ↿⇂  ↿     

• A. i) aufbau principle
  ii) Pauli-Exclusion principle
  iii) Hund's rule
• B. i) Pauli-Exclusion principle
  ii) Hund's rule
  iii) aufbau principle
• C. i) Hund's rule
  ii) aufbau principle
  iii) Pauli-Exclusion principle
• D. i) aufbau principle
  ii) Hund's rule
  iii) Pauli-Exclusion principle

Answer: (A)