Chemistry Thread

[Geoff]

Many thanks for that, Spas, explained in simple enough terms that even I can understand it!

[Existentialist1844]

Name all the elements on the periodic table.

Here ya go.

Here's a link to my favorit online periodic table: http://www.dayah.com/periodic/

Name all the elements on the periodic table.

I haven't memorized it, so what would be the point of the exercise? Memorizing the periodic table isn't required in order to do chemistry. All that is required is access to a periodic table and understanding how to read it- recognizing the periodic trends and remembering the shared properties of the groups. Transition metals are funky.

You havent memorized all of them? What the hell!! You should be ashamed of yourself.

Actually, I was just joking about listing all of them, you big poophead,

[Feck]

[JimC]

Actually, what I like doing with my bright year 10s is to get them thinking about the reasons behind trends in the periodic table. For example, we might look at the Group 1 elements, find consistent changes in melting point and reactivity as you go down the group, then have a discussion (or in reality a Socrates style dialogue) to explore how we can explain this in terms of electron arrangement. Then we have a look at the halogens, where the trend is opposite, but the underlying reasons also help them understand more about electron arrangements.

[The Curious Squid]

As far as the transition metals question goes, isn't it enough to say that the metals can exist in different states because the order that the electrons fill up the shells isn't necessarily the same order in which the electrons are removed from the shells leaving different possibilities for the arrangement of outer electrons that are available for reactions? You don't need to go into the whole 2S2, 2P8 jargon do you?

[The Curious Squid]

Just wanted to add in something very basic as a little bit of help because Spaz's post reminded me of it.

An easy way to remember which reaction is which in a Redox experiment is to use the acronym OILRIG

Oxidation is Loss, Reduction is Gain.

That little sentence saved me more than once in uni.

[ScholasticSpastic]

As far as the transition metals question goes, isn't it enough to say that the metals can exist in different states because the order that the electrons fill up the shells isn't necessarily the same order in which the electrons are removed from the shells leaving different possibilities for the arrangement of outer electrons that are available for reactions? You don't need to go into the whole 2S2, 2P8 jargon do you?

The reason transition metals are so funky is due to the contribution from 'd' sub-shell electrons to their chemical characteristics. It's really hard to understand why they do what they do without getting a good feel for the relative energy levels of the outermost sub-shells and understanding what the Pauli Exclusion Principle has to do with it. It also helps to keep in mind that electrons can be promoted and demoted within shells to obtain lower overall energetic configurations and that sometimes it's more favorable to have a half-filled sub-shell than it is to ditch a bunch of electrons or to try to fill the outer shell.

Damn those 'd' orbitals!

[The Curious Squid]

It's been 3 years since I studied Chemistry so I'm a little rusty with the specifics but I can remember what you're talking about. What I'm saying is do 10th graders need to worry about all that when they can get a simple version that doesn't go into detail about electron shells and d-orbitals?

I'm trying to think up another good question....give me a minute.

[JimC]

It's been 3 years since I studied Chemistry so I'm a little rusty with the specifics but I can remember what you're talking about. What I'm saying is do 10th graders need to worry about all that when they can get a simple version that doesn't go into detail about electron shells and d-orbitals?

I'm trying to think up another good question....give me a minute.

Yeah, that's what I go for, something like your explanation, with the idea that depending the detailed chemistry of the situation, transition metals may have differing oxidation states. Sometimes it is important for kids to know an idea at a basic level, and then return to it, gaining deeper explanations later (the ascending spiral model)

[The Curious Squid]

That's how I was taught and I suppose it worked but I can remember being frustrated in highschool when you would advance and be told that stuff you learned was either not quite correct or in some instances fully erronious.