colors and elements

[AzurePhoenix]

i'm trying to compile some data for class, and would like to know, when you add an element to a flame, and that flame changes color (magnesium=white, potassium=violet, and copper=green-blue) is the resulting color of the flame related to the element's spectral signature, or whatever that's called? And most importantly, is there a site i can go log onto to find what color each element burns, as well as their spectral signature, if they are different.... i'm particularly interested in cobalt, gold, silver and platinum.... i'd really appreciate some help, Thanx

[ed84c]

try thre chemistry & physics handbook, there may be one in the libary, there is more figures in there than you could care to wish for! im pretty sure this features in it.

[budullewraagh]

http://jersey.uoregon.edu/vlab/elements/Elements.html

[Jake712]

whenever you add the element to the flame the element absorbs some enegy (absorbtion) and its electrons jump a new enegy level. Soon after, however, its electrons return to their normal level and emit the light you see (emission). The color of the light is determined by the wavelength of the energy emited by the element as light. Therefore, the color is based on the arrangments of its electrons. Each element has its own spectrum that it emits when it emits this energy. The link budullewraagh posted is a list of these spectrums.

 

Correct me if I'm wrong on this, but i believe that this is how we know what elements the sun contains; because we can look at the spectrum it emits.

[jsatan]

Do a search on google for emissions spectrum and you should be rosy.

Isn’t it just great?

Yeah it true how they knew what the sun is.

[AzurePhoenix]

right, that's how we i.d the composition of luminous stellar bodies (with a spectrometer i think?) i just wasn't quite sure that the flame test and spectral sig. were really correlated. Thanx alot. Mercury's spectral signature covers ten bands of color, so it would burn white, right? I'm fairly sure i've got it.... thanx again.... *hug*

[jdurg]

Mercury has a blue-like color when its vapor is "excited". If you ever see cars driving down the street and their headlights seem really bright and have a blue tint to it, that's because they're probably using mercury vapor lights.

[AzurePhoenix]

ahh, my mistake

[jsatan]

it may seem that it should be white but there has to be a balance in the colours given off, have a look at your light bulb, looks white but its more red than anything.

 

defraction gratings works for this as far as I know, i know it works for hid.

[Primarygun]

What's the colour of chromium metal?

[AzurePhoenix]

i believe chromium is a grayishblue silver, but doesn't it have some unusual properties in the realm of color? Chromium means color... or soemthing like that. and I think it causes the colors to occur in rubies, emeralds, and alexandrite (a stone for which it causes to change color in low light)

[Gilded]

Ooh alexandrites, I'd like one of those for my collection. They happen to be mostly quite expensive & rare buggers though. It's basically BeAl2O4, with minute traces of iron, titanium and the chrome you mentioned. It's quite odd, as other members of the chrysoberyl family don't contain chrome (or then I've been eating mushrooms again).

 

I think the color change goes something like this; sunlight (or fluorescent light) is enough to excite the Cr's electrons to the orbit that causes them to emit green light when they drop back. Unlike in the case of emeralds and rubies, alexandrite has the Cr arranged so that they can emit both green (as is the case with emeralds, in emeralds the green could be vanadium too though) and red (as is the case with rubies), depending on the... err, amount of electron volts? Yeah, that's probably it.

[(*disco*)]

whenever you add the element to the flame the element absorbs some enegy (absorbtion) and its electrons jump a new enegy level. Soon after' date=' however, its electrons return to their normal level and emit the light you see (emission). The color of the light is determined by the wavelength of the energy emited by the element as light. Therefore, the color is based on the arrangments of its electrons. Each element has its own spectrum that it emits when it emits this energy. The link budullewraagh posted is a list of these spectrums.

 

Correct me if I'm wrong on this, but i believe that this is how we know what elements the sun contains; because we can look at the spectrum it emits.[/quote']

 

This is the basis of a lab technique called AAS - Atomic Absorption Spectrophotometry. You can measure Absorption and Transmission.

 

http://en.wikipedia.org/wiki/Spectrophotometer

[AzurePhoenix]

damn, i've searched everywhere, and got plenty of info on how it works and why, but i can't find the visible color emitted by gold, silver, platinum or cobalt!!!! I'm goin' crazy!!!! The problem is that some metals, like the ones i''m most desperately looking for, don't vaporize at the temp. available to a common lab-rat like myself, so noone bothers to log the flame test results one might get if they had an ultra-hot super-high tech blowtorch... maybe i can hold someone really important hostage, and force the government to find the answers i'm looking for. And I don't mean their spectral signature, i mean the actual color a human would see if that light were made visible (like the mercury-vapor thing, or flame-test)

[jdurg]

Well, I believe gold imparts a cranberry/ruby red type color to glass if it's added in small quantities to glassware. It also has a spectral line at around 583 nm, which would explain the red color.

 

I'm fairly confident that cobalt will impart a deep blue color if it's excited. Hence the term 'Cobalt Blue'.

 

Silver has a bunch of spectral lines down in the blue/violet region of the spectrum, a strong doublet in the red section, and a couple of lines in the green area. I would guess that silver would put out a light blue or pinkish color flame.

 

For platinum, well, I don't know. heh

[AzurePhoenix]

jdurg, you are my god, i worship you a thousand times over... if you ever need anything, don't hesitate to ask... i knew platinum would be the tough one

[swansont]

Well' date=' I believe gold imparts a cranberry/ruby red type color to glass if it's added in small quantities to glassware. It also has a spectral line at around 583 nm, which would explain the red color.

[/quote']

 

583 nm is in the yellow region of the visible spectrum. Why does that explain the red?

[AzurePhoenix]

damn... my hopes are finally raised on a flagpole of truth, then they're hit by a meteor, typical

[(*disco*)]

583 nm is in the yellow region of the visible spectrum[/url']. Why does that explain the red?

 

it may emit in a range that is yellow, but our eyes may percieve a different color....?

[Gilded]

583 is quite a rough estimate if jdurg didn't actually check the exact nm amount of the gold's "red" spectre line.

[swansont]

it may emit in a range that is yellow, but our eyes may percieve a different color....?

 

No, I don't think that works.

[swansont]

583 is quite a rough estimate if jdurg didn't actually check the exact nm amount of the gold's "red" spectre line.

 

"Around 600" is a rough estimate. 583 specifies the wavelength to better than 0.2%.

[Gilded]

Whoops, I meant quite accurate estimate, if the exact wavelength wasn't checked by jdurg. Damn, I really, really, really really really should sleep more. I even thought the post through like thrice, and then I make just about the only mistake I can make in it. Great.

[jdurg]

It was an attempt to make a good estimate. I was able to see the absorption spectrum from what is at http://www.webelements.com under the Gold section.