0:03 welcome to the second video for
0:05 chapter four section one on ionic
0:07 bonding in this video we'll be
0:08 predicting the charge of common metallic
0:10 and nonmetallic elements and writing
0:13 their electron configurations
0:14 uh we're going to talk about the
0:16 electric electronic structure of cations
0:17 first and then we'll
0:20 talk about anions later so uh just as a reminder
0:21 reminder
0:23 uh when you are generating an electron
0:24 configuration we use the aufbau
0:26 principle to build up from the bottom
0:28 we put electrons into the most stable
0:30 orbitals first and the least
0:33 stable orbitals last um and when we lose
0:35 electrons when when these elements lose
0:37 electrons to become
0:39 uh ions cations they go they do the
0:41 reverse right they lose the least stable
0:43 electrons the highest in energy
0:45 first and then they lose more stable
0:47 electrons later
0:51 also full shells tend to be more stable
0:58 elements will lose enough lose enough
0:58 electrons to
1:00 sort of mimic the noble gas
1:01 configurations where where the where the
1:03 valence shell is completely full
1:05 uh so we'll talk about these in groups
1:06 because it makes a lot of sense to talk
1:07 about these as as
1:10 sort of periodic trends right um their
1:12 sort of properties uh we'll start out
1:13 with groups one and two so these are gonna
1:14 gonna
1:16 contain you know your common elements
1:18 sodium magnesium calcium potassium
1:20 um if you are interested in biology you
1:22 will recognize all of these guys
1:24 um and a bunch of these other ones as
1:26 well so this is this is group one and
1:27 group two
1:30 these as you might expect tend to lose
1:33 their outermost valence shell and they
1:34 lose their s
1:37 electrons so if you look at sodium for example
1:38 example
1:42 um sodium the electron configuration for sodium
1:43 sodium
1:47 is 1s2 2s2
1:51 2p6 and then 3s1
1:53 so we're looking at sodium it's last
1:54 electron its valence electron is in the
1:57 3s and there's only one of them
2:00 uh we can also write this if we want to as
2:01 as
2:06 neon plus 3s1
2:09 when sodium uh forms an ion it tends to
2:10 form a
2:13 one plus cation because it loses this 3s
2:16 electron and it becomes uh
2:21 it just has the configuration of neon
2:23 uh group two elements so for example
2:24 calcium and i'll scroll up just a little
2:25 bit so you can see this little better so
2:27 if we're looking at calcium we can think
2:28 about calcium
2:29 uh and i'm just gonna write the
2:31 abbreviated form of calcium's electron
2:33 configuration so it is argon
2:37 and then its valence shell is 4s2
2:40 so this element tends to lose both of its
2:41 its
2:45 s electrons and it forms a two plus ion
2:47 which has the electron configuration
2:50 that is just the same as arkon
2:52 so groups one and two tend to lose their
2:54 complete valence shell which is their s
2:56 orbital and uh so group one tends to become
2:57 become
3:00 a plus one and group two tends to become
3:05 we'll think about a different set of
3:06 metals next so we'll think about
3:09 uh the metals that are in groups 13
3:10 through 17 and
3:12 that's these guys um i've drawn a really
3:13 awkward triangle around here
3:15 we're going to ignore for now the
3:18 metalloids they do some weird things uh
3:19 we're going to focus on
3:22 the metals over here in the p block so
3:23 they also
3:26 tend to lose their uh valence shell right
3:26 right
3:28 they tend to lose their valence shell
3:30 but for these there's
3:32 not only s electrons but now there's p
3:33 electrons as well
3:36 so if we take aluminum as an exception
3:39 we can write its electron configuration
3:43 as neon and then 3s2
3:46 3p1 so you would predict
3:48 that aluminum would lose all of its
3:50 valence electrons it would lose all of
3:51 its um
3:55 its third valence
3:57 electrons and that is in fact the case
4:00 aluminum becomes a three plus ion and it
4:02 has the same electron configuration
4:05 as neon there are some exceptions near
4:06 the bottom of the table
4:09 so these guys down here in the p block
4:11 but down near the bottom of the table
4:14 um have a weird thing that happens where
4:15 you can you can predict that thallium is
4:16 going to make a three plus just like
4:18 aluminum it will lose
4:20 um all of its valence electrons lead
4:21 it's going to make a four plus tin same
4:23 thing's gonna make a four plus bismuth
4:24 is going to make a five plus
4:26 uh cation but they actually also have
4:28 something else that happens
4:29 where they keep their valence s
4:31 electrons and this is called the inert
4:38 and essentially what happens is the uh
4:40 the s electrons have a relatively low energy
4:41 energy
4:44 and um they just keep them so in
4:46 addition to making the sort of
4:49 predicted three plus four plus and five
4:50 plus ions they actually make
4:53 so tantalum for or sorry thallium makes a
4:54 a
4:59 three plus but it also makes a one plus
5:02 uh and tin and lead tend to make
5:04 uh four plus the expected four plus but
5:05 they also make two pluses
5:08 and then bismuth um tends to make
5:10 the expected five plus ion but it also
5:12 makes uh
5:15 wow uh bismuth will also make a
5:17 a less expected three plus ion due to
5:19 this inner pair effect where it keeps
5:20 its valence
5:26 one additional uh exception is mercury
5:28 mercury is actually a transition metal
5:29 here but um
5:32 it can form both uh mercury two plus and
5:34 it can actually form this
5:36 uh diatomic ion where there's actually a
5:38 bond between the two mercury
5:41 ion atoms and then it makes uh
5:49 next we'll talk about transition metals
5:51 uh transition metals are a little bit
5:54 weird they do a lot of things one of the
5:55 things that's really key to remember
5:56 with transition
5:58 metals is when you're using the aufbau
6:00 principle to fill
6:02 your valence electrons when you're
6:04 building an electron configuration
6:07 you fill the four s's and then you build
6:09 and then you fill the three d's
6:12 but it turns out that the four s's
6:13 actually empty first
6:15 so the valence s electrons are actually
6:17 less stable than the d electrons when
6:18 you are
6:20 losing electrons to form cations and so
6:22 you tend to lose those before you
6:26 lose the d electrons uh also there are multiple
6:26 multiple
6:30 options uh for for your transition metals
6:30 metals
6:33 and uh that that is just an unfortunate
6:34 effect of there's
6:37 um yeah the the dd shell is
6:41 uh complicated um one of the
6:44 the really common ones is iron so iron has
6:45 has
6:47 an electron configuration if we write it
6:49 out it is
6:53 argon with 3d6
6:56 and 4s2 so
6:58 if you look at this you might say well i
7:00 think that it would probably lose its 4s
7:03 electrons and yes in fact it does it
7:04 will form
7:07 an iron two plus ion which is uh
7:10 has the electron configuration of just
7:11 argon with the
7:15 3d6 electrons but it actually will also
7:16 lose one electron from the
7:19 the d shell sometimes and you can
7:20 actually also get
7:23 an iron three plus and that essentially
7:24 is just
7:26 uh it has the electron configuration of argon
7:27 argon
7:31 with uh d five um
7:32 and this actually points out that we
7:34 talked about full shells
7:36 have uh are extra stable there's they're
7:38 a little bit more stable but actually
7:41 half shells um the half uh so if you
7:42 have five electrons
7:45 in five out of 10 electrons in your d or
7:46 three out of six electrons in your p
7:48 orbital um there's actually that last
7:51 electron is slightly more stable
7:53 um and so that's why iron tends to make a
7:54 a
7:57 a three plus as well so
7:59 in general we're not going to ask you to
8:01 memorize um
8:03 transition metals because they do form multiple
8:04 multiple
8:06 uh multiple cations there are a few that
8:08 you need to know
8:10 um so one way that i like to remember the
8:11 the
8:14 zinc is going to make a two plus and
8:17 silver is going to make a one plus and
8:19 the way that i remember that is that
8:22 it's a backward staircase going down
8:24 we know from the last section that
8:26 aluminum is a plus three
8:28 so it's a three two one so aluminum is a
8:29 plus three
8:31 zinc is a two plus and then silver tends
8:32 to make a one plus
8:34 um so those are the only ones that are
8:36 commonly known but the rest of them will
8:38 uh will will either give you the charge or
8:39 or
8:41 give you some other information about
8:43 them and then real briefly the inner
8:44 transition metals or the
8:47 lanthanide and actinide series that's
8:48 your f block
8:51 they will often form three plus
8:53 ions they tend to lose both of their s
8:54 electrons and then one
8:57 either f d electron um this happens
8:58 because when you have
9:00 uh when you're when your valence shell
9:02 is is this high in energy
9:04 uh it's um it's hard to tell the
9:06 difference between all the orbitals the
9:08 the energy levels are actually quite
9:10 quite close together um and so we're not
9:11 really going to deal with these we don't
9:12 really deal with these in gen chem very
9:14 much but uh it's good to know that they
9:15 do tend to form
9:20 all right and then the last thing we're
9:21 going to talk about is the electronic
9:22 structure of
9:26 anions so anions are usually non-metals
9:29 um they are um you know they're
9:30 they're these guys right these are these
9:32 are the guys that are going to tend to form
9:32 form
9:36 our anions and uh
9:38 if they follow the same principles um
9:40 the full shell is going to be
9:42 in general more stable and these ones
9:44 though when they're forming anions they
9:46 are gaining electrons so rather than
9:48 losing electrons all the way down to the
9:50 the last noble gas um they're actually
9:52 going to gain enough electrons to
9:55 uh to have the same uh electron
9:56 configuration as the noble gas at the
9:57 end of their row
10:00 uh or that full valence shell so for
10:02 example oxygen
10:05 oh sorry got a cat in my lap
10:08 for example oxygen uh is gonna often
10:09 form a
10:11 two minus ion uh and it will have the
10:13 same electron configuration as neon
10:17 so let me just show you that so oxygen
10:20 the electron configuration of oxygen is 1s2
10:21 1s2
10:24 2s2 2p4
10:26 um i can write that with helium but i'm
10:28 just going to do it longhand because
10:31 it's not very long and it tends to make the
10:31 the
10:34 two minus anion which means it's gained
10:35 two electrons
10:38 and we just stick them straight in the last
10:39 last
10:41 orbital that isn't full so uh the
10:43 valence or the electron configuration
10:43 for this
10:47 um oxide ion is going to be 2s2
10:50 and then 2p6 which
10:52 is equivalent to the electron configuration
10:53 configuration
10:57 of neon which has that full
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