# Orbital diagram in which the Aufbau principle is violated [closed]

The orbital diagram in which the Aufbau principle is violated is:

The answer given for this question is 3, but according to me if asked for Hund's rule violation then it would be 1, as electrons are not distributed among the subshell in such a way to give maximum number of unpaired electron with parallel spin.

## closed as unclear what you're asking by Mithoron, bon, Jan, airhuff, pentavalentcarbonOct 22 '17 at 14:01

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• Ok. So what is your question? – Tan Yong Boon Oct 22 '17 at 8:35
• That's the ground state for carbon. The pairing energy is lower than the difference between $2s$ and $2p$, so you definitely pair in $2s$ before moving up to $2p$. – Zhe Oct 22 '17 at 12:15
• But you’re not being asked for Hund’s rule violation …? – Jan Oct 22 '17 at 13:20
• None of these violate Hund's rule. Aufbau is violated in 3 because $s$ was not filled before moving on to $p$. – Zhe Oct 22 '17 at 20:53