[Solvay_1927]

Ian - you're right.  And yes, I know you answered the question that goofkid actually meant to ask.

And as for musical expertise, DrB is a composer.  (We're all waiting for him to upload some of his music onto the forum.) []

[another_someone]

Beyond the original question is I suppose the question of how much do we actually need any longer to synthesise the various compounds in the real world, and how far computer modelling can do it for us?

[goofkid (OP)]

Thx all! so lemmy get this straight, the majority says there ARE many undiscovered materials that are just waiting... right? cool. []

Goofkid

[chris]

quote:Originally posted by DoctorBeaver

Every substance in the periodic table is an element. That means they are not combinations. All that can be done is to add extra protons (I think) thereby transforming them into heavier elements. Even so, I think I'm right in saying that there is an upper limit to how far that process can be taken

Just to clarify the above point, so there's no mistake, each element has its own atomic number which is equal to the number of protons in the nucleus. Adding a proton would therefore change one element into the next one in the series. In other words, hydrogen (1 proton) would turn into helium (2 protons).

But different forms of the same element can exist, and what distinguishes them is the number of neutrons in the nucleus. These alternative forms of the same element are referred to as isotopes. They are essentially the same element, but they contain different numbers of neutrons in the nucleus, and therefore have different atomic weights (referred to as the RAM or relative atomic mass), and physical properties, such as being radioactive.

For instance, hydrogen (sometimes called protium) has an atomic mass of 1. It consists of 1 proton in the nucleus and 1 electron whizzing around the nucleus. It has 2 other isotopes - deuterium, which has a mass of 2 and consists of a nucleus containing 1 proton and 1 neutron, and tritium, which has a mass of 3 with a nucleus containing 1 proton and 2 neutrons. This latter form is radioactive. In nature, the ratio of hydrogen to deuterium is about 5000:1.

Another example is carbon, which we use for carbon dating things - this involves comparing the ratios of carbon-12 to carbon-14.

Now here's a little conundrum for you. If you look at a periodic table the relative atomic mass for chlorine is 35.5. Given that neutrons and protons both weigh "1", how can you arrive at an atom which apparently has half a neutron in it ?

Chris

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx

[Soul Surfer]

The chemical atomic weights are those you find when doing experiments in the lab.  Most elements are mixtures of different proportions of the stable isotopes of that element.  It happens that chlorine cosists of two isotopes on weight 35 and the other 37 and about 25% is of the 37 so the mean atomic weight is 35.5.

Also the actual atomic weights of the individual isotopes are not precisely round numbers because the neutron and the proton do not have exactly the same mass (1.007593 for the proton and 1.008982 for the neutron) and you also have to allow a bit for the electrons and the binding energy of the neuleus  for example the atomic weight of hydrogen is 1.008142 and that of Helium 4.003873

Its also interesting to note that elements with an odd atomic number only tend to have one or at most two stable isotopes while even numbered ones have lots. Tin atomic no 50 has nine or ten!

Learn, create, test and tell
evolution rules in all things
God says so!

[gsmollin]

quote:Originally posted by DoctorBeaver

quote:And to add to Ian's answer, there are TWELVE notes in the musical scale, not eight

Only in Western music. Arabic, Indian etc have more

There are twelve notes in a tempered musical scale. Not all western scales are tempered, although that's the modern scale. The original western (Greek) scales were pentatonic, and if you singe acapella you are using one. But this wasn't supposed to be a music theory post. It's a good subject though.

"F = ma, E = mc^2, and you can't push a string."

[chris]

Soul Surfer - thanks for that very precise answer - I was hoping we'd catch some people out with that, but you didn't waste any time getting in there !

Given the content of your answer, I think you might be interested in one of the items in this week's Nature podcast, out tomorrow at 1800 (GMT) - http://www.nature.com/nature/podcast

Chris

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx

[Soul Surfer]

Thanks for the link must try to catch up with that.  Presumably you are the same chris.  Also note you are a UCL person although I went there and did physics in Harry Masseys time.  Paul Davies is a contemorary of me.

Decided to give up on reading Nature and Science last year 'cos I just didn't have the time what with New Scientist, Scientific American,  IEE, IOP, RAS and BAA stuff to read.   New Scientist also usually had articles on the stuff I was mainly interested in a week or two later and I could always backtrack at the library if I needed detail.

Learn, create, test and tell
evolution rules in all things
God says so!

[chris]

Yes UCL to do a neuroscence degree then Cambrdge for medcne and a PhD on gene therapy.

Chrs

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx

[goofkid (OP)]

O and another thing.

WHERE can i get elements from the periodic table so i can experiment with them!! This is important cuz i can't apply what i learned!
Thx [^]

Goofkid

[Soul Surfer]

They are all found in varying proprtions in most of the rocks and even sea water you just have to do a bit of chemistry to extract them. []

Learn, create, test and tell
evolution rules in all things
God says so!

[goofkid (OP)]

quote:Originally posted by Soul Surfer

They are all found in varying proprtions in most of the rocks and even sea water you just have to do a bit of chemistry to extract them. []

O yea... maybe i could even go the the dead sea to get some NaCl, and then go all the way to Africa to get some Au, and then dig deep to get some C in hopes of finding diamonds! Yay!! I figured it out!


Goofkid

[geoffspear]

quote: dig deep to get some C

You don't have to dig very deep to find carbon.  Every organic molecule (including the ones your body is made of) is built from carbon, among other things.