Home › MCQs › NEET Chemistry › Question #7357
Back to Questions
NEET Chemistry QUESTION #7357
Question 1
When the principal quantum number \(n = 6\), the correct sequence for filling electrons into subshells follows:
  • \(ns \to (n-2)f \to (n-1)d \to np\)✔️
  • \(ns \to (n-1)d \to (n-2)f \to np\)
  • \(ns \to (n-2)f \to np \to (n-1)d\)
  • \(ns \to np \to (n-1)d \to (n-2)f\)
Correct Answer Explanation
Aufbau principle (for n = 6):
The filling order follows the \((n+\ell)\) rule (lowest \(n+\ell\) fills first):
  • 6s: \(n+\ell = 6\)
  • 4f: \(n+\ell = 7\)
  • 5d: \(n+\ell = 7\) (higher \(n\), so after 4f)
  • 6p: \(n+\ell = 8\)
So: \(6s \to 4f \to 5d \to 6p\), which is \(ns \to (n-2)f \to (n-1)d \to np\).