Questions tagged [elements]

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11
votes
5answers
22k views

Why is spectrum obtained by sunlight, said to be continuous?

My teacher spoke about atomic spectra today, and he explained that, unlike the spectrum obtained by analyzing the sunlight, the spectra of atoms are not continuous. I have a question about this - ...
0
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2answers
2k views

How close are humans to creating gold from other elements?

Gold is made in supernovae. How close are humans to doing that? Or is it even possible to do that unless gravity is absurdly high?
3
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1answer
330 views

How did neodymium magnets get their name?

Like in the question. Why neodymium magnets (Nd2Fe14B) are called "neodymium magnets"? Why not boron magnets? Or iron magnets?
2
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0answers
66 views

How common is compromised reference data for physical properties of materials and elements?

This question concerns Monte Carlo simulation of electron scattering in complex material structures, especially the reliability of publicly available source codes and reference data for physical ...
108
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6answers
51k views

Why are most metals gray/silver?

Why do most metals (iron, tin, aluminum, lead, zinc, tungsten, nickel, etc.) appear silver or gray in color? (What atomic characteristics determine the color?) What makes copper and gold have ...
10
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4answers
7k views

Is there a Tungsten alloy more dense than gold?

This thought came from researching a previous question. In the spirit of our get-rich-quick scheming, I looked up element densities and prices near gold. Element Density ($g/cm^3$) Value ($\$/kg$) ...
6
votes
2answers
1k views

Is it possible to create a new element that doesn't exist in the universe?

When I say something new I do not refer to something already made like H,O etc and when I mean something new I do not refer to a transformation like tritium to helium and gold. If so how ?(I mean is ...
-5
votes
1answer
109 views

diffrent elements from diffrent elements [closed]

Do we get elements from other elements ? Somebody said they believed the world was visited by aliens and they made slavs of us and then amde us mine gold for them then they leave us to grow into what ...
6
votes
1answer
384 views

Are new elements still being created?

Last I heard, there were 115 elements (natural and artificial, of course). Are there more still being made? If so, why? I thought this question would be more appropriate on the physics site rather ...
3
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0answers
60 views

In the αβγ cosmology paper, how do the authors assume the integral of density over time in the early universe?

In the famous Alpher-Bethe-Gamow paper, the authors say: "it is necessary to assume the integral of $\sigma_n dt$ during the building-up period is equal to $5 \times 10^4 \frac{\text{g sec}}{\text{cm}^...
9
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3answers
4k views

Why are synthetic elements unstable?

So far 20 synthetic elements have been synthesized. All are unstable, decaying with half-lives between years and milliseconds. Why is that?
2
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4answers
466 views

How many years will the nuclear resources of Earth last for generating electricity?

We have plenty of nuclear reactors around the world. They are consuming nuclear resources of the Earth. Nuclear elements are scarcer than the other elements, aren't they? When are we going to run out ...
0
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1answer
2k views

Reference for phase diagrams of elements [duplicate]

I am trying to answer this question: What is the pressure inside a sealed container with liquid nitrogen at room temperature? Can you help me find a good online reference for phase diagrams. I am ...
1
vote
3answers
1k views

In the known universe, would an atom not present in our periodic table exist?

I have watched this movie Battleship. In it the researchers say this piece of metal is alien because we cant find this metal on earth. So that would mean somewhere else in the universe any of the ...
3
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1answer
597 views

Unknown isotope

Problem description: The most common isotope of a single nucleus stripped of its electrons is accelerated through a potential difference of 1225V and fired horizontally into a B-field directed ...
8
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1answer
173 views

Why does Omega Centauri have a distinct chemical signature from the rest of the Milky Way?

In answering a question about the orbital path of Omega Centauri, I learned that it has a distinct chemical signature from the rest of the Milky Way. Basically, it is very rich in s-process elements, ...
1
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1answer
148 views

Why don't the actinides start at neptunium?

In their physical and chemical properties, actinium, thorium, protactinium, and uranium are respectively similar to lanthanum, hafnium, tantalum, and tungsten, and thus would seem to belong ...
14
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1answer
653 views

Island of Stability

When I was much younger, I remember being fascinated by the thought of an Island of Stability at very high atomic numbers. However, I have not heard much on this and I was wondering Did this idea ...
2
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1answer
389 views

How much lead is there in the universe?

I know there is around 10^80 atoms in the observable universe, but is there any estimate the amount of lead in the universe (within a couple magnitudes of 10)?
20
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3answers
11k views

Why is oxygen the third most abundant element?

I was reading the article Oxygen finally spotted in space today in which it stated Oxygen is the third most abundant element in the cosmos, after hydrogen and helium. Why would oxygen take the ...
10
votes
1answer
14k views

What is so special about iron?

I remember reading something about how iron was a highly stable element. Ever since then, I have looked at iron fry pans with new-found respect. However, in a recent discussion I was unable to ...
4
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2answers
262 views

Phase of Elements

There are 11 gaseous elements and two liquid elements at standard temperature and pressure. The rest are solid. Can phase be predicted from quantum mechanical principles?
6
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6answers
22k views

Iodine-131 half-life and reality

Iodine is a chemical element with symbol I and atomic number 53. There is currently a lot of discussions regarding radioactivity in Japan, and iodine-131. Iodine-131 has a half-life of 8 days. Does it ...
36
votes
3answers
33k views

What is the origin of elements heavier than iron?

In all the discussions about how the heavy elements in the universe are forged in the guts of stars and especially during a star's death, I usually hear that once the star begins fusing lighter atoms ...
17
votes
4answers
8k views

Why does amount of protons define how matter is?

My question might sound convoluted but my mind is twisting right now so my apologies in advanced. Why is it that when I have one proton and one electron it is Hydrogen a clear flammable gas, and ...
26
votes
3answers
4k views

Why the distribution of elements on Earth?

I've been wondering exactly why the elements are distributed the way they are on Earth. The heavier elements have their origins in the centers of stars, or in supernovae. After the death of the stars, ...
8
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2answers
1k views

How were noble gases discovered?

Noble gases are chemically neutral. They don't react with anything. So, how were they discovered?

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