Ionization Energy: Periodic Table Trend Explained Clearly

hello everyone and welcome back my name is mr covald and in this video i'm going to continue to go over periodic trends

and we're going to go over ionization energy in this video okay let's get into this so

periodic trends so again it all goes back to uh the trend in effective nuclear charge

what's happening in the nucleus is it getting bigger what's happening with shielding is there shielding going

on what's happening to energy levels are we adding energy levels things like that and it always goes back to coulomb's law

as well remember so as electrons get farther from the nucleus there's a not as strong of a pull on those

electrons the bigger the charge right bigger charges have stronger pulls on each other and so that's going to be the

factors that we want to think about when we're thinking about periodic trends and so

right now uh on the board i have here uh so the periodic table

and so here are the groups it's kind of weird but that's the way it is with my drawing um

so we have this group three group four five six and so on i don't have seven and eight

uh because of lack of room um and then i have three periods or at least two periods and then i have uh

potassium in the third third period so

when we're looking at ionization energy we have to understand that ion is what ionization energy is

so ionization energy is the energy required to remove one electron from a neutral atom so

we're removing the first electron from a neutral atom how much energy does that take okay

so we got to think about um is it is it going to be easier or harder to take an electron away from an atom if

the nucleus uh has a larger charge right so if the charge in the nucleus is larger and the

electrons are feeling a larger pull a larger attractive force by the nucleus then it's going to be

harder to remove that electron and it's going to take more energy right so therefore we would expect that the

stronger the pull on the electron right the stronger the pull the stronger the

attractive force on the electron the harder it is to remove that electron from the atom and therefore we're going

to need to put more energy in so more energy required okay

so there are two factors that affect the pull on the electron the first factor is

the size of the charge right and when we're thinking about size of charges we're thinking about the nucleus so

more charge in the nucleus means more pull

and so and also we need to take in the shielding effect as well because some of that shielding is going to counteract

some of that sides of the charge that's why we need to look at effective nuclear charge because the effective nuclear

charge takes into consideration the shielding effect and so we can look at the effective

nuclear charge and say okay is the effective nuclear charge large or small if the effective nuclear charge is large

then that means greater attractive force which means that you're going to need more energy to remove the electron

therefore higher ionization energy okay the other thing we want to look at is these uh how far

the electrons are from the nucleus so remember distance matters if we're thinking about coulomb's law right so

the closer they the charges are the stronger the attractive force the farther those charges get away from each

other this weaker the attractive force right so again if the attractive force is weaker it's

easier to take away the electron it doesn't take as much energy so less energy means

less ionization energy so those are the things we want to keep in

mind so let's look at our periodic table let's look at the effective charge let's look at the size of the atom right so if

we can remember what's happening with the size of the atom and y then we can remember the ionization

energy so we saw with the size of the atom that as you go across the size of the atom

decreases why because the effective nuclear charge is increasing

so what does that mean so the larger the charge the more attractive force the more it's going to pull the electrons in

so therefore the electrons are feeling a greater force as you go across the periodic table

so this electron here is not feeling as much of an attractive

force as this electron so if this electron is only feeling an effective force of one a plus one charge

then this one will be easier to remove because it's not held as strongly this one

has a larger attractive force so it's got an effective nuclear charge of plus two so it's feeling a stronger pull

and therefore it's going to be it's going to require more energy to remove this electron from this atom that it

does this atom and so on so this these electrons feel an effective force of a plus three

so removing one of these electrons is going to require more energy because they feel a greater force

and so on so because the effective nuclear charge is increasing going across the periodic

table therefore we would expect the ionization energy to also increase so the amount of

energy required to remove the electron should increase as well because the electrons are feeling a greater

attractive force and so it's going to be harder to remove that electron which means it requires more energy

okay what about going down the group we saw before

that going down a group the effective nuclear charge pretty much stays the same

and again the reason it stays the same is because although the the nuclear charge is getting larger

so is the shielding so the shielding is increasing as well so they counteract each other

so the effective nuclear charge is pretty much the same plus one so the uh the attractive force of the

nucleus on the electron is not changing all that much it does change um but what we definitely notice here is as you

go down you're adding a larger shell so the valence electron is getting farther from the positive nucleus and so because

that valence electron is getting farther from the positive nucleus that positive nucleus is not able to attract the

electron as strongly if it was closer because remember as the electron gets farther from the nucleus that attractive

force decreases so this electron here we would expect to have a stronger force

on it and therefore removing this electron would be harder and therefore require more energy therefore more

ionization energy than say this one here because it's farther away so this electron is farther from the nucleus so

this would be not as strongly attracted so it'd be easier to take this electron away and

therefore it would be easier to take this electron away because it's even farther from the nucleus so we would

expect that the ionization energy the amount of energy needed to take the electron away would decrease going down

a group because the you're getting farther from the nucleus and again farther from the

nucleus means weaker attractive force easier to remove the electron and so

going back to my periodic table here we could write the trend as follows

so as you are going across the periodic table this way then ionization energy increases

right so ie ionization energy increases

going across and it also increases going up a group or decreases going down

a group either way you want to think about it so ionization energy increases going up the group so then the

overall pattern in the periodic table is that going from this corner to this corner you have

increasing ionization energy and that's the pattern

and so we can see that we can understand this pattern we can remember this pattern here this

trend in the periodic table with regard to ionization energy because we understand the trend going on with the

effective nuclear charge and shielding and what's going on with the sizes of the atom because of that so when we're

going down a group we're adding energy levels electrons are getting farther away as we go across a period the

effective nuclear charge is increasing pulling electrons in closer more strongly

and so you could see how the trend of atomic size or radius is matching or related to

ionization energy as well so if you can remember the trend of size then it's easy to remember the trend for

ionization energy because they're both based on the same things which is effective nuclear charge and the

distance from the nucleus i hope this is helpful if you like this video please smash that

like button please subscribe to my channel hit that notification bell so you'll be notified by other videos i put

out put a comment in the comment section let me know what you think and if you have any questions thanks for joining me

have a great day