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10. Periodic Properties of the Elements

The Electron Configuration

10. Periodic Properties of the Elements

The Electron Configuration

The electron configuration of an element is the distribution of its electrons within atomic orbitals.

The Electron Configuration

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The Electron Configuration

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now, before we can talk about electron configurations. Realized first that Mendeleev organized the elements in the periodic table through periodic law in periodic land says that when arranged by increasing atomic weight, elements in the same group share similar chemical properties. These properties would influence their electron arrangements and by extension, their configurations. It would affect their trends and reactivity and their atomic structures. So remember, in order to first understand electronic configurations, we need to go into periodic law first, and it helps us to understand how the periodic table itself is organized.

Periodic Law: elements in same group arranged by increasing atomic weight, share chemical properties, which influence electron arrangements, trends and atomic structure.

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The Electron Configuration

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As we stated earlier, the periodic law influences the electron arrangements of the elements, and the electron orbital diagrams are the visual representation of electrons within orbital's. Now we're going to say, Here we have what are called degenerate orbital's. These are electrons in the same set of orbital's having same energy and they're filled using Huns rule. Now, Hunt rules says that these degenerate orbital's our first half filled before being totally filled. So if we take a look here, we have our s sub level or s sub shell, as can hold a maximum of two electrons. It has one orbital. Within that orbital, we have two electrons. One spins up, one spins down. So that would mean that the sub level has a maximum of two electrons. For p sub level, we have three orbital's following hunts rule. We would have filled them first, so we go up, up, up Each orbital we know can hold a maximum of two electron. So we come back around down, down, down. So the piece of level holds a maximum of six electrons for D. We have five orbital's here. Hans Rule says we have filled them first since they're all d set of orbital's. They all have similar energy. So then we come back around down, down, down, down, down for total up 10 electrons And finally, the F sub level has seven of these orbital's half filled them again, according to Hunts rule. So when we have for them, according to Hunt's role, come back around so totally fill them in. When we do that, we get a total of 14 electrons. So just remember periodic law influences the electron arrangement of elements. And it's these orbital diagrams that depict the visual representation of electron within any given orbital based on sub shall level or sub shell uh, letter. So just keep that in mind as can hold a maximum of two electrons. P can hold up to six Deacon, hold up to 10 and F can hold up to 14

According to Hund's Rule, degenerate orbitals are first half filled before being totally filled.

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The Electron Configuration Example 1

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here, it says we need to properly fill in the orbital's oven. Adams that possesses eight electrons within its D set of Orbital's. Now we know that these are D set of orbital's because there's five of them. We have to fill in eight electrons, Remember, since they're all the same set of orbital types being deep, they all have the same energy and therefore are degenerate. We would have filled them based on Hans role. So we go up, up, up, up, up For our first five, we need to fill in eight. So come back around. Down, down, down. So we stopped there because again, we only have eight electrons to fill in. So here we don't need to completely fill in. The last two there will be left just one electron in each. So this would be the way to properly fill in these d set of orbital's that have eight total electrons

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Problem

Problem

Which electron configuration represents a violation of Hund's Rule?

A

B

C

D

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The Electron Configuration

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when writing the electron configuration of an element. It's important that it represents the distribution of electrons from one s two to s 22 p, and so on within Orbital's using the off bowel principle. Now with the awe found principle, it says starting with one s, we're gonna have electrons filling lower energy orbital's before moving on to higher energy orbital's. We begin with one s when we're doing the full ground state electron configuration, often element or an ion to help us with this, you could take the off ball diagram approach when we start out with one s, then we move on loop back around to to us. Then we look back around 22 P, then 23 us. Then we loop back around 23 p and then for us. Then continuously. Look back around 23 D 24 p to five s. Now this is our off bomb diagram. India five diagram we have here want us all the way down to eight us. Then we have two p to three on 27 p, Then we have three d to 60 and then we have four F and five f another way we could look at determining the electron configuration has to do more with the periodic table. So if you click on the next video, let's reimagine what the periodic table will look like when dealing with the electron configuration of elements and ion.

According to Auf Bau Principle, starting from 1s, electrons fill lower energy orbitals before filling higher energy orbitals.

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The Electron Configuration

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so here. If we re imagine the periodic table will see in this depiction now realize here we have blue, We have yellow, We have purple, only have read sectors. Now each of these is called the bloc s. The S block is what's in blue. This is the P block, the D block and the F block. Remember, the S sub level has one orbital and that one orbital can hold a maximum of two electrons, Which is why the S block is these two columns to represent the two maximum electrons that the sub level could hold. The P sub level has three organs, right and each one again can hold a maximum of two electrons. So P theoretically can hold a maximum of six electrons. That's why the P block has 12345 and six slots for it. D can have up to 10 electrons because it has five orbital's, and if you count, you'll see in here there's 10 spots and then for the F sub levels, they can hold up to 14 electrons. And if you were to count these rows in red, you see, they come out to 14 now realize here that in this periodic table, the first slot here, which represents hydrogen, starts off our electron configuration as one s one. Then, as we move to the next one, we add another electron. So helium is one as to then when we get to the second row, since we're in the second row, we now have to. This is still the S block. So this is one s two to s one and it continues. Onward and onward. Over. Here we go. One asked to two s 22 p one. So, following this pattern, this would be three us for us five s, six s and seven s. And then here this would be three p four p five p six p and seven p. When we go to the D block, realize that it's gonna drop down by one. So here this is for us. But then when we go to D block, it drops down by one number. So now it's three D. This would be 40 five d and now notice how this number goes from 57 to 72. That's because 58 to 71 are here. Remember this this red line here says that this entire red row exist in between 57 72 and then we go between 104 because 90 to 103 is down here. These are your F blocks. They also dropped down by one number. So this is four F and five F. So, basically, if you can re imagine the periodic table in this fashion, you can use it to figure out the electron configuration of any elements or ion given to you. So we're gonna put this periodic table to use in order to do future electron configurations.

Electron configuration of Boron (Z= 5) is 1s² 2s²2p¹.

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example

The Electron Configuration Example 2

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to help us with this example. Question. I decided to leave this periodic table up so we can see how to best use it here. It says right, the ground state electron configuration for the following element here we're dealing with flooring and they tell us that it has an atomic number of nine, which means it has nine electrons on this periodic table. We find flooring right here. Ground state means that we're going to start out with one s orbital and work our way up to flooring. So we're gonna count the flooring. So we'd say one s to one asked to two s two because of 12 slots and then we have to count toe f. So that would be two p were in the two p ro. And how many slots do we have? Thio count to to get the flooring. aN:aN:000NaN p five. So here this would be the ground state electron configuration off the flooring Adam, and realize here that these are the number of electrons. So when you add them up, two plus two plus by that gives me nine electrons which is related to the atomic number here off flooring. Remember when an element is neutral, its atomic number tells us both the number of protons and the number of electrons. So again, rely on this depiction of the periodic table to help guide you to the right electron configuration off any element or ion given to you.

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Problem

Problem

Which electron configuration represents a violation of the Auf Bau Principle?

A

B

C

D

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Problem

Problem

Identify the element with the given electron orbital diagram.

A

Silicon

B

Fluorine

C

Sulfur

D

Chlorine

E

Phosphorus

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Problem

Problem

Write the electron configuration and electron orbital diagram for the following element:
Mn (Z = 25)

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Problem

Problem

Write the ground-state electron configuration for the following element:
Lead (Z = 82)

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