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Current time:0:00Total duration:5:34

Video transcript

in the last video we saw the classification of elements in two groups on the periodic table we stopped with a definition for a transition metal there are two ways to think about transition metals so one way to think about it would be when some teachers say transition metal they're talking about elements found from groups 3 through group 12 so all the elements in here some people consider these to be the transition metals so these are the elements found in the d-block right so we're talking about D orbitals here so you have to understand electron configurations for this video so that's one way to think about the the transition metals but that way is it maybe a little bit too general sometimes so there is another definition which you'll find on the IU pack website IU pack is an acronym for International Union of pure and applied chemistry and they say that a transition element refers to an element whose atom has an incomplete d subshell so when you're talking about the d orbitals we already know there are five D orbitals and each orbital holds of maximum of two electrons so 5 times 2 is 10 so it tend to be the maximum number of electrons you could fit in your D orbitals or your d subshell so let's count that out on our periodic table so 10 so 1 2 3 4 5 6 7 8 9 10 for our d block so let's let's go ahead and write an electron configuration for a transition metal and let's see how how that applies to our definition from IU pack so let's let's write an electron configuration for iron so here's I write here and if I wanted to write an electronic configuration let's say I want to do noble gas notation so once again I'm assuming that that you that you know how to do this already so I won't spend too much time talking about it but if I want to write a a noble gas configuration I would go to argon which is the noble gas before iron now I put argon in brackets like that and that takes me to the fourth energy level or the fourth period on the PRI table and then just looking at the periodic table I can say oh that would be for us one for us to so I can write for s2 here and and then I'm in my D orbital so again just looking at the periodic table to write my electron configuration I would say one two three four five six electrons so that would be three D D at six and I could have written this 3 D 6 4s 2 and right now both are considered to be correct answers and I won't get into I won't get into a discussion about the order of filling of these orbitals in this video so I'll save that for another video this video is only talking about definitions and identifying elements on the periodic table and so either one of these would be a correct electronic configuration and when I look at the the D orbitals alright so when I look at the D orbitals for the electron configuration I can see that there are 6 electrons in my D orbitals well that's an incomplete d subshell right because i can fit a total of 10 into my d orbitals and so iron would be an example of an element that has whose atom has an incomplete d subshell so iron is a transition metal let's write the electron configuration for zinc so let's find zinc over here so right there on our periodic table so if I wanted to write the electron configuration for zinc once again I would go to the noble gas before it which is argon so I would put in brackets argon right here and then once again takes me to the fourth energy level so 4s1 4s2 so for s2 and then I count over from I D electrons one two three four five six seven eight nine and ten so it'd be three d-10 and once again I could have written that argon in brackets 3 D 10 for s2 so it doesn't matter um so let's uh let's think about the definition for a transition metal an element whose atom has an incomplete d subshell well if I look at the D orbitals for zinc right they are completely full I have 10 electrons in my D orbitals and so this is a complete D sub shell so this does not meet the definition for a transition element now also in the definition to talks about cations right so let's think about the cation that zinc would form zinc would go to zinc two-plus so if I wanted to write the electron configuration for zinc two-plus I need to think about where does ink lose two electrons so if you're going from a neutral atom of zinc right to zinc two-plus you would have to lose two electrons well I already know that those two electrons are going to be lost from the 4s orbital so we're going to lose these two electrons right here on your electron configuration and so you'd be left with 3d10 and once again you have a cation that has a complete d subshell you've completely filled your D orbitals and so the cation does not have an incomplete d subshell which means that it doesn't fit our our technical definition for a transition element from iu packs and so and so once again there there are two ways to thinking about it one's a very general way so you might you might hear someone talk about an element from groups 3 to 12 as being a transition metal or you might find people who are you are a little bit more more particular about the definition who who go along without you pack so it's good to be aware of both ways of thinking about it