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51
votes
6answers
10k 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 ...
16
votes
2answers
3k 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 ...
10
votes
2answers
819 views

How is the number of electrons in an atom found?

I was wondering, what type of experiments were held to identify the number of electrons in an atom? (For example, how do we say that carbon has 6 electrons and magnesium 12.) I would like someone to ...
7
votes
1answer
3k 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 ...
7
votes
2answers
1k 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 (g/cm^3) (dollars/kg) Uranium ...
6
votes
2answers
698 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 ...
6
votes
2answers
353 views

How were noble gases discovered?

Noble gases are chemically neutral. They don't react with anything. So, how were they discovered?
6
votes
1answer
111 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, ...
4
votes
1answer
256 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 ...
4
votes
1answer
77 views

Where is quantum physics with regards to the periodic table?

In his Lecture's on Physics (circa 1960's) Richard Feynman wrote that so far physics has only been able to model (solve) the hydrogen and helium atoms. So now, more than 50 year's later where are we ...
4
votes
1answer
861 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?
4
votes
2answers
234 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?
4
votes
1answer
86 views

How do scientists estimate elemental-abundance in the universe?

I understand how cosmological observations can estimate the amount of 'baryonic matter' in the universe, but what I don't understand is how scientists can estimate the abundance of a particular ...
4
votes
1answer
41 views

Lifetime of undiscovered element and its calculation

Reading about nuclear models, nuclear physics and the mythical ``stability island'' I just wondered about the next question: How can the lifetime of any undiscovered superheavy element be calculated ...
4
votes
3answers
1k views

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

My sir spoke about atomic spectra today. Sir said that, unlike the spectrum obtained by analyzing the sunlight, the spectra of atoms are not continuous. I got a doubt here, i,e even the sunlight ...
4
votes
1answer
58 views

Are there any established theories as to why dubnium-268 and 270 have such high stability for a trans-actinide?

Dubnium-268 has a half life of 29h and 270, 23.15h. I know of the island of stability but if dubnium is in it, the island is very small as only rutherfordium has isotopes that approach the same ...
3
votes
3answers
121 views

Do different plasmas from different elements have different properties?

If so, what are some differences? Like between iron and gold? EDIT: Sorry, I need to clarify: By 'difference' I mean... do they retain their chemical properties from more normal temperatures? Like is ...
3
votes
1answer
68 views

Why are some elemental materials grey?

How does grey occur in elemental materials such as metals? I believe that grey arises from the simultaneous reflection and absorption of all colors of the spectrum (in different atoms of course), as ...
3
votes
1answer
220 views

Why is cesium used to measure time in atomic clocks?

Seconds are measured by the frequency emission of cesium. Why is a frequency from the emission spectrum of cesium used as the standard in defining a second? Why particularly cesium?
3
votes
1answer
384 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 ...
3
votes
1answer
42 views

What is the heaviest element possible produced in a supernova?

So, I would imagine this question would have been asked here long ago but the suggested questions and Google is really letting me down now. So, as far as I can tell Plutonium is the heaviest naturally ...
3
votes
0answers
45 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 ...
2
votes
4answers
154 views

Can nuclear transmutation be observed in real time?

Ignoring the quantum zeno effect (if possible?), can we observe in real-time the transformation of one element to another? I'm talking about an amount visible to the naked eye where one could see ...
2
votes
4answers
365 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 ...
2
votes
1answer
72 views

Would other intelligent life in the Universe be likely to construct the same periodic table of the elements? [closed]

Is the structure of the periodic table fundamental enough that other forms of intelligent life would likely structure their own listing of the elements in the same way (i.e. are there other ways of ...
2
votes
1answer
28 views

Periodic Table and strong fields at high Z

There is a known "phenomenon" recalled by Greiner et al. in several of his books related to hypothetical elements with Z>172: in some point arount this Z, the nuclear field is strong enough to pop out ...
2
votes
0answers
42 views

How do experimental physicists know the decay path of transuranium elements ahead of time?

I have been watching (and enjoying) Dr. Poliakoff's YouTube videos on the synthesis of transuranium elements like Roentgenium and Copernicium, which decay so quickly that they are identified (if I ...
1
vote
3answers
704 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 ...
1
vote
2answers
160 views

Do all elements spectrum lines fall within the visible light range?

I was wondering if whether we were extremely lucky to have found spectral (absorption) lines of astronomical objects because they fell within the visible light range or if there something intrinsic ...
1
vote
1answer
93 views

What is the state of the art in particle detection and localization

I am researching methods to detect the position of radioactive materials (emitting gamma and beta particles), and would like to know what current methods are used to do this. What type of sensors are ...
1
vote
1answer
200 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)?
1
vote
1answer
81 views

Is the rarity of elements related to their position on the periodic table?

I understand that most of the matter in the universe (aside from dark matter and energy of course) is hydrogen (74%) and helium (23-25%), leaving the remainder of the elements at only a few percent. ...
1
vote
2answers
59 views

When talking about atomic mass, how is $E=mc^2$ factored in? [duplicate]

When talking about atomic mass in the periodic table of elements, is this number the mass of the element at rest? If I understand correctly, the (relativistic) mass of an element will increase as the ...
1
vote
1answer
108 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 ...
1
vote
0answers
53 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 ...
0
votes
2answers
886 views

How close are humans to creating gold from other elements?

Gold is made when dying stars collide. How close are humans to doing that? Or is it even possible to do that unless gravity is absurdly high?
0
votes
1answer
91 views

Is there any material that is NOT conductive and IS magnetically attractive?

Is there any material which is NOT conductive and IS magnetically attractive? I am in need of a material which I can shape and use within a machine. It must be very attracted to magnets similarly to ...
0
votes
1answer
56 views

How can a paramagnetic element be a permanent magnet?

I'm just starting with magnetism and stuff and I was reading about different types of magnetism. Such as ferromagnetism, anti-ferromagnetism and paramagnetism. If I understand it correctly, examples ...
0
votes
0answers
18 views

What are the principle factors that limit $\beta$ decay to elements with atomic number, Z 100 or less?

I learned for the first time in Eric Scerri's new book A Tale of 7 Elements that $\beta$ decay does not occur for elements with atomic number, Z > 100. I did some further web research on this subject ...
0
votes
1answer
587 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
votes
2answers
46 views

Creating elements without using the basic elements

Have there ever been created an element in the history (I'm talking about the 20 well known synthetics element) without using any other of the available elements from the nature? For example, element ...
-1
votes
2answers
597 views

Formula for critical mass? Critical mass of polonium?

I'm looking for the critical mass of Polonium; is there a formula? E.g.:$$\text{Neutrons / Protons}\cdot\text{ Constant = X kg}$$ There is a little table in the Wikipedia. E.g.: ...
-4
votes
1answer
68 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 ...
-7
votes
1answer
147 views

Could Carbon 14 have been created before the Big Bang? [closed]

Here is my interest in learning about the source of Carbon 14(The Stuff I think they use for Carbon Dating). I might even be asking the question wrong, but here goes. Source of the Elements? Does not ...