How to use the periodic table to write electron configuration easily

hello everyone and welcome back my name is mr covald and in this video i'm going to show you how you can use the periodic

table to find the electron affinity of any

atom on the periodic table okay so let's get into this but before we get into this

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now let's get into this so so we have our periodic table we're

going to set this up so that way we can figure out what the electron configurations are

so the first thing we need to do is we're going to number the sides here so

on your periodic table along the left hand side

you will see that the rows are numbered and we call these rows periods so in the periodic table we call them periods so

each period or row has a number so we're going to number from 1

to 7 on the bottom so let's go ahead and do that so if you have your own periodic table

you can number this as well yours maybe look a little bit different than mine but that's okay

so we're gonna put a one a two a three

a four a five six and seven okay so we've got those

periods numbered we got the rows numbered so next

we have to block out certain things or certain parts of our periodic table so that we

can recognize them as different parts you can kind of see that they're different

uh right away but we're going to kind of highlight uh the different parts of the periodic table

so let's get some different colors here okay so this first part here

uh we're gonna look at this part here you can see that this part is kind of by itself

so we're going to color that red now the thing i want to point out is that for the purposes of

electron configuration we'll notice that helium is over here but we're going to move it over here for

the purposes of electron configuration we're going to put it in this group here the reason for that is because helium

kind of behaves as far as electron configurations go it goes over here mainly because

that first energy level that's filled up only has a 1s2 if you remember from electron configurations

so the 1s sublevel can only fill two electrons in that sublevel

and so that goes to helium helium kind of fits

there in this group here so i'm kind of jumping ahead of myself so let's let's kind of

put this over here so we're going to kind of cross this out a little bit

so we're going to and we're going to move that over here so we got

h e okay so

let us kind of cro color this a little bit or our outline

we're going to outline this with red you could pick your own color it doesn't have to be red i'm just using

red because that's available but you can use whatever color you want all right so that's kind of separated

we're gonna uh now separate the next one or like highlight the next one and the next one

we're gonna look at is this block here so this block here seems to be one by itself or

it seems to stick out a little bit so we're going to highlight that a little bit more

so we're going to put we're gonna use blue or i'm gonna use blue you can use

whatever color you want okay and the next one

this part here seems to be a different part

so we're going to highlight this okay

and then finally we're going to highlight

this part here we're going to use orange so i'm going to use orange here again you can use

whatever color you want you can make it all pretty mine's not that pretty

okay so here we go so now i want to point something out to you so this is going to be mind-blowing

it was mind-blowing to me so if you've never seen this before get ready to

have your world rocked so we've learned that in electronic

figurations you have the s sublevel and so you think okay so think about how many orbitals are in that

that sublevel we only ever have one s orbital every s sublevel has only one s orbital

and how many electrons can fit into that 1s orbital 2 maximum right

so if we look here how many elements wide is this part here if we were to count

how many elements wide is that two okay

so far so good now now let's think about the p sublevel the p sublevel

has how many p orbitals it has

three right you have the p x the p y and the p z orbitals that are oriented in space differently along the axes

and each of those can hold how many electrons each two so each

p orbital holds two electrons you have three p orbitals that's a total of six electrons

and how many elements wide is this block if you count how many do you count

one two three four five six it's six wide interesting

interesting what about the d sub level right you have the d sub level how many d orbitals

do you have at the d sub level anyone bueller

bueller we have five d orbitals so five d orbitals

each d orbital holds two electrons max and that means you have a total of

ten electrons in the d orbital and if i was to ask you

to count the width of this block right here how many elements wide would that be

let's see one two three four five six seven eight nine ten wow

and finally we have this block here so remember we have the f sub level f sub level

can has seven seven orbitals each orbital holds two electrons i think you know where i'm

going with this yes that's right seven orbitals two electrons each 14

electrons i think you can guess the width of this block here 1 2 3 4 5 6 7 8 9 10 11 12 13 14. amazing

amazing um that is amazing because this table

uh was originally i mean when it was set up it wasn't exactly set up this way but i

mean it was pretty much set up this way before we knew anything about

protons electrons neutrons right and so the periodic table when it was

organized uh eventually in like 1914 it was organized by mosley to according to

atomic number but before that it was organized by atomic mass but atomic number atomic mass doesn't

really change as a couple it's like maybe uh maybe four elements switch places

based on they differ based on mass versus atomic number but it's pretty much this

way so now we have quantum theory we have

orbitals we have orbital diagrams we have energy levels and you can see that the different sub levels match perfectly

with the periodic table that is amazing i don't know about you but that just blows my mind

so what we're going to do now is we are going to label the blocks so since since the s sublevel

has two electrons max and this is too wide we're going to call that or they call that i i didn't come up with this

this is called the s block okay

next since we have this block here is six wide and the p

sub level ten is is uh has a maximum of six electrons we're going to call this

p block next here since the d sublevel has 10

electrons max and this is 10 elements wide this is called

the d block and finally since this part here

matches with the f sublevel because the f sub level holds a maximum of 14 electrons this has 14 elements across

this is going to be the f block the f block

okay so now we have our periodic table set up and we broken up into s p d and f block

and we have our periods numbered now

the thing to remember is these periods uh match up

with the energy level that you are at one a couple things i want to add so

the other thing you want to add here is i'm going to use orange again

so we have to number these differently here these rows are going to be numbered

differently and these two rows are going to be numbered slightly differently um

so for when we're getting into the d block we're going to have a 3 here so instead

of a 4 this is going to be 3 and these are going to differ by minus 1. so 5

minus one is four six minus one is five seven minus one is six

okay and then for these two

uh these guys get inserted into here

right after barium or i should say lanthium and actium so you'll see 58 you get 57

58 and then this is 89 90 for thorium so these two rows

actually get inserted here and so when we do that when we're going from six to

when we're doing f the these are going to be labeled these are going to be numbered i should

say 2 less than the row or period you're in so this is

6. so this row here is going to have

a four so that's going to be four and then this row here is going to be in

the seven row but when we get here that's going to be a five so it's two less than the row

that you're in okay so we have our table set up

so now you can use your periodic table to write electron configurations

how does that work well let me show you i'm going to move this over

and we're going to do a couple of examples

okay i'm gonna use a piece of paper and pen pen so that

you can see it more easily i'm gonna zoom in a little bit so we can see the periodic table

maybe that's yeah there we go okay so

that's good enough for now all right so here's my piece of paper

all right let's see how this is done so the way you use the periodic table to write your electron configurations is is

this you first need to know what element you have and how many electrons that element

has we're assuming neutral so if you're given an element and you want to know how many electrons it has if

it's a neutral element neutral atom then the electrons are going to be equal to the protons and the protons are given to

you by the atomic number so remember the atomic number is this top number up here so the atomic number of nickel is 28 the

atomic number of of arsenic is 33 and so on so

if you know the number of electrons then all you need to do remember the number of electrons are being added to

your orbital diagram you start from the lowest energy level to moving up to the highest going

through the different sub-levels and the sub-levels differ in energy as well right so the s orbital is lower in

energy than the p the p is lower than the d and the d is lower than the f so you're going to fill in the s and then

the p and then the d and the f and things like that so

so the periodic table actually tells you what to do because all you need to do

is start always at number one helium so you just start at

the beginning of your periodic table and you write down the row that you're in because remember the row corresponds

to the energy level the block that you're in the block corresponds to the sub level

and the number of elements that you go through to get through that block and that's going to correspond to the number

of electrons so let's do a quick example um let's do carbon carbon i'll do a simple one here so carbon is here

carbon's number six okay so six electrons so all i'm gonna do is i'm gonna

start it here a hydrogen here and i'm gonna go through each row right each row

until i get to carbon but and i'm going in numerical order you're going in numerical order so

one and then two for helium three four five six right and as i'm going numerically

through the periodic table i'm writing down the row that i go through the block that i go through and how many elements

in that block i go through okay so uh carbon let's do carbon so c for carbon

so i start at hydrogen i got to go through hydrogen i got to start from one and i got to get to six

so as i'm going through the elements i am writing down the row

the block and the number of number of elements so

i start here i have hydrogen and helium i'm going through those because i gotta get to number six so one and two are

done so that's row one so i'm writing out one i'm in the s

block s and i gotta go through two elements so two

now i'm done with that row or i'm here there's nothing else so i got to go numerically to lithium

now i'm in the second row so that's 2. what what block am i in s s

and then i have to go through these two to get to six so i go three four so i go through two of those elements so that's

two now i jump over to the p block number five is next

so i'm now in the p block i'm still in the second period second row so i'm it's going to

be two and then i put p and how many elements do i have to go

through one two so i have to go through two elements so that's a two

for the p so that ladies and gentlemen is the electron configuration for carbon that's it that's how you use the

periodic table okay let's keep going let's do uh let's do a larger one let's do iron

i like iron no let's do cobalt my last name is covalt with the v let's

do cobalt so that's going to be co yes

cobalt is my favorite element okay so it's the same thing so now i have 27 electrons right so number 27

means i have 27 protons i'm going to assume that the atom is neutral so that means i have 27 electrons so i'm going

to go from 1 all the way to 27 and as i'm going

through the periodic table i'm writing down the the period or row that i'm in the

block them in and the number of elements i have to go through because the row

these numbers here and these numbers here and these numbers here right uh represent the energy level

of that sublevel and the block here represents the sub

sublevels that you're in and the number of elements you go through represents the number of

electrons you're putting in into that sublevel okay let's let's get into this so i'm

starting with hydrogen and i'm working my way numerically until i get to cobalt

okay so i go through the first row i'm in first row s block so 1

s i got to go through those two so that's going to be a two

i continue to number three now i'm in the period number two that's going to be the second energy level i'm in the s

block so that's 2s and i'm going through the 2s 3 4 so that's 2.

and i jump over now i'm it's still in the second row second period so that's still a two

so it's going to be now 2p because now i'm in the p block and i have to get to cobalt so i got to

go through all of these one two three four five six all the way to ten so that's going to be six electrons

in the p sublevel second sub level now i'm all the way over at neon so i got to keep

going because i got to get to number 27 i'm only at number 10. so keep going so i go to 11. now i'm at sodium i'm in a

period three so third energy level s block so that's 3 s

i got to go through sodium and magnesium

so that's 2 so that's 3s2 and then i gotta jump over again to aluminum

so now i'm in the uh the p block again i'm still in the third the third row third energy level third

period so that's going to be 3p i gotta go through one two three four five six to get to 18. again my goal is

cobalt as 27 so i got to go through these so that's six elements six electrons

in that sublevel now i'm at argonne now i gotta jump down to number 19 which is potassium in the fourth period so

that's energy level number four s block so that's 4s

and that's 2 1 2. i got to go through 2 to get to 20 24 calcium so 4s2 now i'm jumping to the

d block here so 20 to 21 i'm in the d block notice the number has gone down one so that's 3d

not 4d 3d so 3d and i got to count one two three four five six seven so that's going to be seven

in the 3d sub level and that ladies and gentlemen is the

electron configuration for for the uh element cobalt

okay let's do one more let's do a longer one because i want to kind of discuss something here

last one uh we're gonna do um

let's see we're gonna do let's do uh polonium

p-o or we could do lead let's do lead

let's do lead number 82 we're going to do 82 electrons so lead pb so same thing

um we have 82 electrons so we're gonna start with one hydrogen and work our way through

to get to lead and then that's gonna involve the f block and i'll show you something

there okay so

we're going to start with hydrogen 1s2 so we're going to go through

the 1s we go through the two elements so we're going through these two

elements one two two's there so we're putting helium

there right so one two now we go down to three we're in the second period second energy so 2s

we go through two elements there so that's two electrons added to the 2s

and we jump over again to the p block that's going to be 2p we're in the second period still so

that's energy level 2 p we go through 6 elements we're going to 82 in this one so that's

going to be 6 neon jump down to 11 sodium we're in period three so that's

third energy level s block three s and we're going through two the two elements

jumping across to the p block here still in period three

so we're going to go through these six elements we're in the third three p sub level

so that's three third row third period p block six elements through so that's three

p six okay now we're at argon again we're gonna jump down to 19 for potassium

that's the fourth period so that 4s we're in the s block so for

fourth energy level s sublevel we're gonna go through these two potassium calcium so that's

two now we're in the d block with number twenty one so again three d so we're at

third energy level d sublevel so 3d we're going to go through all 10 of those so that's going to be 10

3d 10. okay we're going to have to give ourselves

some room here so i'm going to go down here so after

the d block we go back to four i forgot to write that down we should uh

we should go back to the four here so when we go back to the p we're going to go back to the original

numbers so 4 5 6

and 7. so here

here we're going to go from okay 3d 10 to 4p again so now we're in the p block

we're back at the fourth level so four p we're right down here so four p and

we're going to go through all six elements so that's six electrons now i'm at krypton i gotta jump down from 36 to

37 rubidium so now i'm in the fifth period which is energy level five and

i'm in the s block so that's 5s so i'm going to 5s i go through those two

so then i'm going to be 5s2 now i'm jump into the d block again so that's 4d and i'm going to go through

all 10 of those elements so that's 4 d 10.

so now i'm at cadmium and now i'm jumping to 49 with it which

is indium and that's going to be back to 5. so that's 5p i'm in the p block again so 5

p i'm going through all six elements to get the xenon so that's 6 electrons in

the 5p sublevel now i'm at xenon and i keep going so because i want to get to 82 i'm not

there yet so 54 jumping down to 55 cesium six

uh sixth period so period number six six uh uh energy level number six so this is 6s i'm in the s block

now so that's 6 s 2 because i got to go through these two and now this is where um we don't really

follow the periodic table exactly and you'll notice here uh that lanthium seems to be

in the d block right lathium and actinium uh but and then we're inserting uh

ce after 58 we're not going to follow exactly how this periodic table is

normally