Sub-topic 1
2026 · National One-Eighth
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Maximum electrons in a subshell from quantum numbers n and l
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Sub-topic 2
2026 · National One-Eighth
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Unpaired electrons in an anomalous ground-state configuration
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Sub-topic 3
2024 · National One-Eighth
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Possible quantum numbers (n, l, ml) for a given subshell
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Sub-topic 4
2025 · Regional Championship
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Identifying a valid set of quantum numbers (n, l, ml, ms) for an electron in a given orbital or subshell
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Sub-topic 5
2025 · Regional Championship
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Identifying a valid set of quantum numbers (n, l, ml, ms) for an electron in a given orbital or subshell
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Sub-topic 6
2024 · National Preliminary
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Reactivity trends: electron count vs electron configuration (true/false)
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Sub-topic 7
2023 · National Preliminary
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Identifying an element from its electron configuration
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Sub-topic 8
2013 · National Preliminary
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Correct statement of the pauli exclusion principle (true/false)
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Sub-topic 9
2013 · National Preliminary
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Common valencies of a transition element from its valence-shell configuration (4s2 3d6)
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Sub-topic 10
2013 · National Preliminary
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Inferring valence-shell configuration from a wide range of observed valencies
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Sub-topic 11
2014 · National Final
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The energy level at which the f subshell first appears
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Sub-topic 12
2014 · National Final
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Maximum number of electrons in an f subshell
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Sub-topic 13
2014 · National Final
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Collective name for elements filling the 4f or 5f subshells
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Sub-topic 14
2018 · National Preliminary
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The aufbau principle for ground-state electron configuration
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Sub-topic 15
2018 · National Preliminary
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The pauli exclusion principle for electron quantum numbers
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Sub-topic 16
2018 · National Preliminary
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Hund's rule for filling degenerate orbitals singly before pairing
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Sub-topic 17
2021 · National Preliminary
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Cobalt has 3 unpaired electrons in its 3d subshell, via hund's rule
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Sub-topic 18
2021 · National Preliminary
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8 electrons occupy the n=3 shell of the ca2+ ion
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Sub-topic 19
2022 · National Preliminary
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Complete quantum numbers for a valence electron of beryllium
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Sub-topic 20
2022 · National Preliminary
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Complete quantum numbers for a valence electron of carbon
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Sub-topic 21
2022 · National Preliminary
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Complete quantum numbers for a valence electron of sodium
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Sub-topic 22
2022 · National Preliminary
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True or false: no two electrons can occupy the same subshell (pauli's principle)
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Sub-topic 23
2022 · National Preliminary
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True or false: no two electrons can have the same energy (pauli's principle)
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Sub-topic 24
2022 · National Preliminary
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True or false: no two electrons in the same orbital can have the same spin (pauli's principle)
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