 ## General Chemistry

Learn the toughest concepts covered in Chemistry with step-by-step video tutorials and practice problems by world-class tutors

9. Quantum Mechanics

# Quantum Numbers: Nodes

A node is the region in an atom with zero electron density and where an electron is least likely to exist.

Nodes
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concept

## Quantum Numbers: Nodes 45s
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with quantum mechanics were obsessed with finding the location of an electron. But just remember that a vast majority of the atom itself is empty space. Since the electrons are so small, we're gonna say a node is the region within an atom where the probability of finding an electron is zero. We need to say that this region has zero electron density. We're gonna say electron shell is the region where electrons reside with highest probability, which is what we've been focusing on in terms of quantum mechanics. Now to determine the total number of nodes, just remember that it's equal to your principal quantum number. N minus. What? So if you know your principal quantum number for a given set of orbital's so tracked one and that be equal to the number of notes
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example

## Quantum Numbers: Nodes Example 1 22s
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how many total nodes are present in a four d orbital. Now, remember, the total number of nodes is equal to end minus one. Since the number here is four, that means we're dealing with electrons found within the fourth shell of an atom. So an equals four so four minus one would mean that we have three total notes present within a four d orbital.
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concept

## Quantum Numbers: Nodes 1m
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now a node can be further classified as either a radial note or angular note. Now a radio note is just the spiritual region that separates the different shells. Here we have Shell one, which is n equals one shell to which is an equals two and then shell three. The space between them are your radio nose, and the number of radio nose is equal to N minus your annual mentum quantum number L plus one. Your angular node is are basically flat cones or planes that dissecting orbital's oven Adam. So this is more three dimensional. Basically, what you need to know here is that the number of angular nodes is equal to just L, which is your angular momentum quantum number. So we now know how to calculate the total number of note by N minus one. Those total number of nodes could be further separated into either radio notes or angular nodes. Here we have their formulas and purple boxes, which means it's up to you to memorize them.
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example

## Quantum Numbers: Nodes Example 2 38s
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here, we need to determine the number of radio nodes that exist for five F orbital. Remember, the number of radio nodes is equal to N minus l plus one. Since the number of the orbital is five, that tells us it's the fifth shell oven. Adam. So unequal spy. Since the letter is eff that tells us what l is. Remember when the letter is f R sub global letter, that means that l equals three, so that be three plus one. So this comes out toe five minus four, which means that there's only one radio node for five F orbital.
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Problem

Which atomic orbital has the fewest angular nodes?

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Problem

Which atomic orbital has the greatest number of radial nodes? 