Electrons follow certain rules when filling atomic orbitals. Complete the activities below to see how well you understand the rules used to describe how electrons fill atomic orbitals.
In the first activity, use the Aufbau principle to place the energy levels in the correct order from top to bottom, beginning with 1s2 at the top. Keep trying until the orbitals appear in the correct order.
1s2
2s2
2p6
3s2
3p6
4s2
3d10
4p6
5s2
Now, see how well you understand Hund's rule and the Pauli exclusion principle by completing this activity. Answer the question on each slide, then check your answer.
Orbital diagram that uses lines to represent atomic orbitals and arrows to represent electron filling. The diagram has the following attributes from bottom to top:
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The 1s row has one line, and on that line are two arrows. The first is an up arrow, and the second is a down arrow.
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The 2s row has one line, and on that line are two arrows. The first is an up arrow, and the second is a down arrow.
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The 2p row has three lines. On the first line is an up arrow and a down arrow. On the second line is an up arrow. The third line is empty.
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The 3s row has one line, and that line is empty.
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The 3p row has three lines, and those lines are empty.
Based on Hund's rule, is this the correct way to show the electron arrangement for Nitrogen (N)? Explain.
No. According to Hund's rule, when there are multiple orbitals with the same energy, every orbital must have one electron before any orbital will get a second. Since there are three orbitals in the 2p energy level, the three electrons must go into separate orbitals before doubling. Below is the correct electron arrangement.
Orbital diagram that uses lines to represent atomic orbitals and arrows to represent electron filling. The diagram has the following attributes from bottom to top:
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The 1s row has one line, and on that line are two arrows. The first is an up arrow, and the second is a down arrow.
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The 2s row has one line, and on that line are two arrows. The first is an up arrow, and the second is a down arrow.
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The 2p row has three lines. On each line is an up arrow.
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The 3s row has one line, and that line is empty.
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The 3p row has three lines, and those lines are empty.
Orbital diagram that uses lines to represent atomic orbitals and arrows to represent electron filling. The diagram has the following attributes from bottom to top:
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The 1s row has one line, and on that line are up two arrows.
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The 2s row has one line, and on that line are two up arrows.
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The 2p row has three lines, and on each line is an up arrow.
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The 3s row has one line, and that line is empty.
Based on Pauli's exclusion principle, what must be done to correct this electron arrangement?
According to Pauli's exclusion principle, no two electrons in an atom can have identical quantum numbers. The two electrons in 1s have the same n, ℓ, mℓ, ms numbers. This is the same for the two electrons in 2s. To provide different quantum numbers for one of the electrons in each pair, the spin is changed from a positive (+½) to a negative (-½) orientation.
Orbital diagram that uses lines to represent atomic orbitals and arrows to represent electron filling. The diagram has the following attributes from bottom to top:
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The 1s row has one line, and on that line are two arrows. The first is an up arrow, and the second is a down arrow.
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The 2s row has one line, and on that line are two arrows. The first is an up arrow, and the second is a down arrow.
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The 2p row has three lines, and on each line is an up arrow.
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The 3s row has one line, and that line is empty.
