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Hi there.
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This is question number 87.
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Question number 87 has three parts to it, an a, a b and a c.
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Part a wants to know how many sub -levels we have when we're on the second main energy level.
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So let's think about what that means.
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That means a principal quantum number of two.
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That would be our second main energy level.
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When the principal quantum number is two, the angular momentum quantum number, or l, is an integer between zero, and n minus 1.
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So that gives us just two possible options, 0 or 1.
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When l equals 0, that corresponds to an s orbital.
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When l equals 1, that corresponds to p orbitals.
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With the point being here, that we have two sub -levels, the s and the p.
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Okay, moving to part b.
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Part b asks us, which of any of these sub -levels contain a set of equivalent orbitals? so s only has one orbital, but p does have a set of equivalent orbitals.
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There's one p orbital that sets up along the y -axis, one along the x -axis in space, and one along the z -axis.
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So in other words, we have three p orbitals that are equivalent.
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So the p orbitals are equivalent...