Questions tagged [elements]

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Why can a non-Metalloid be a Semiconductor?

I was reading that the first description of a semiconductor material was made by Michael Faraday in 1833 and published in Experimental Researches in Electricity.-Fourth Series (https://www....
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Why do elements, as they have more protons, need a higher amount of neutrons to stabilise them? [duplicate]

I've seen the graphs of the stability line but I can't find any reason as to why this happens, I understand radiation, just not why radiation needs to occur in the first place if that makes sense.
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How can a proton in a nucleus decay into neutron and positron in β+ decay if neutrons have greater mass than a proton? [duplicate]

I'm guessing it has something to do with mass defect/binding energy??
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What is the standard explanation for tungstens abnormal high Pauling electronegativity?

The electronegativity of tungsten does not follow the common trend along the periodic table.
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Why is it when an atom gains a proton it is said to become an 'atom' of a different element?

My confusion lies in that the number of protons in the nucleus will increase but is the number of electrons assumed to automatically follow suit such that the result is a neutral atom with equal ...
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What is the name of the instrument that separates substances using an electromagnetic field, similar to spectrography

As far as I remember, the elements of the substance are passed across an electromagnetic field in such a way that they seperate as the electromagnetic field alters their trajectory. I also seem to ...
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6 votes
1 answer
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Large difference between the atomic sizes of uranium and thorium

According to Villars and Daams [Journal of Alloys and Compounds, 197 (1993) 177] the atomic volume of U is $2.073\times10^{-2}\,\mathrm{nm^3}$, whereas that of Th is much larger, $3.295\times 10^{-2}\,...
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How were the electrons, protons counted in an atom?

The title says it all! In high school I remember it being taught as a religion, I had to believe the count (hydrogen has 1 proton, carbon has 6 etc...) , but how can I be sure I was told the truth?
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Is there an online resource for fusion outcomes of various elements at various energy levels?

I'm looking to find a chart of nuclides, their potential fusion products and measured energy levels, in a similar vein as NuDat 3, but for fusion. It doesn't need to be cleanly formatted like NuDat, ...
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The physical materials (elements and compounds) of the JWST

How many different periodic table elements and compounds are used in the JWST, and where are they used in the telescope? My current list is the following, but I am surely missing many others. Can you ...
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Number of Spins Up and Down (Neutron and Proton)

I would like to know that if I was given an isotope, can I know the number of up (down) spins for neutron and proton? For example for Ge-73, what steps should I take in order to know the number of ...
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Why can't one calculate the energy of the one electron Uranium ion state with the Dirac equation?

In the link, Solving Dirac for one electron atom/ion the energy for the one electron $s_1$ shell is calculated as $$ E=m_{\mu}c^2\left( 1 - \frac{1}{\sqrt{1+\left( \frac{\alpha Z}{n-j-1/2 + \sqrt{(j+1/...
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What is the Hydrogen and Helium composition of the Sun in terms of their different states?

What is the Hydrogen and Helium composition of the Sun in terms of: Hydrogen: (1) molecular, (2) metallic and (3) ionized compositions? and Helium: (1) atomic, (2) metallic and (3) ionized ...
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Specific heat of ionised Helium in the Sun?

What is the specific heat of ionised Helium, given as ergs/g/K? This seems to be very difficult find on the internet. This is in the context calculating the total heat of the Sun which is given as ...
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How to make a new element from an existing one? [closed]

So my question is, how can I create a new synthetic element from some existing element. I want to create eka-francium. Now, what would be the best way for me to may it? Should I use a particle ...
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Why we do not get naturally occurring elements with atomic number greater than 92? [duplicate]

Why we do not get naturally occurring elements with atomic number greater than 92? I know that some arguments suggests that the reason is that all the elements with atomic number from 93 are highly ...
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Does every element have a half-life?

Will every element slowly decay into something else? Or do some isotopes have infinite half-lives?
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Why is Zirconium neutron transparent while Hafnium is such a neutron absorber?

Out of curiosity I've been researching about Hafnium and Zirconium. I'm curious as to why Hafnium (below Zirconium on the periodic table) is so often used in control rods, while Zirconium is ...
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Heat of Sublimation of GaAs and SiC

I am trying to find values for the heat of sublimation of GaAs and SiC, but can't find anything. I also tried searching for the heat of fusion and vaporization, to calculate the heat of sublimation ...
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Is atom vibration (not speed) correlated with temperature?

As far as I know every atom vibrates / oscillates / I don't know what it's called in English with a frequency, specific for its element. I don't mean the velocity of the atom, which defines ...
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If for heavier atoms to form, you need a lot of pressure, then why do we say that the early universe was too hot for atoms to form?

I have read this question: Over the next 380,000 years, the universe gradually cooled down enough for the sub-atomic particles to condense and form the first Hydrogen atoms After the big bang As far ...
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Is liquid lead better gamma ray absorber than solid lead?

Is liquid lead better gamma ray absorber than solid lead? Can this be compared with the fact that an el.conductor has more resistance to current at higher temperatures? If yes could it be used in ...
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1 answer
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When elements inside the Sun form plasma is there any stratification as densities of different cores are practicaly same?

When elements inside the Sun form plasma is there any stratification as densities of different cores are practicaly same?Where do electrons accumulate? I pressume it may depend on electron to core ...
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2 votes
1 answer
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Is there a highest possible atomic number?

I know that atoms with higher atomic numbers tend to become more and more unstable and decay quicker the higher the atomic number goes. Is there a limit to this where the time it takes for the atom to ...
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1 answer
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Physical microscopic origin of vapor pressure and relation to bond strength

Currently, I am examining the vapor pressure of the elements as a function of temperature within the periodic table (as can be found from this resource from TU Wien https://www.iap.tuwien.ac.at/www/...
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1 answer
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What is the fastest heat can travel? The perfect solid heat sink

What dictates the conductivity of heat in an element or medium? Consider the shape, volume, area, and distance heat travels from vibrating atom to atom, not through the excitement of the an atom ...
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1 vote
3 answers
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Is the nuclear mass density constant for different nuclei and shape of the nucleus

I was reading the Wikipedia page on nuclear density when I came upon a problem. (I haven't yet been introduced to nuclear physics.) What form does the nucleus have? Is it spherical? How is it possible ...
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1 answer
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Why is Palladium-108 "theoretically capable of spontaneous fission?"

I was just reading Wikipedia's page on palladium isotopes and I noticed the note about Palladium-108. It says "theoretically capable of spontaneous fission", but I don't find that explained ...
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Does the number of atoms per kilogram of a given element decrease as you go up in atomic mass?

This is kind of straightforward. Because as atoms get heavier, the more protons, neutrons, and electrons they have. I would assume that it would take fewer of them to equal a pound. This seems ...
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4 answers
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Why do "relativistic effects" come into play, when dealing with superheavy atoms?

I have now read on the Wikipedia pages for unbihexium, unbinilium, and copernicium that these elements will not behave similarly to their forebears because of “relativistic effects”. When I read about ...
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Extrema in the Table of Nuclides [closed]

Symbolic picture of a nuclid chart: I would like to know for which $Z$ the area in the nuclide map has the greatest width and for which $N$ and the greatest height. Does anyone know? Note: I don't ...
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Why is the number of isotopes of an element bounded?

Is there a known reason why any given element has finitely many isotopes? Here I mean both stable and unstable isotopes. If we know this, do we have a reason why, for a given element, are the isotopes ...
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Height of capillary rise

Are there any tabular data in which you can find the values of the height of the capillary rise depending on the radius of the capillary? The type of liquid or capillary does not matter.
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Why does the binding energy per nucleon rise as the nucleon number rises, then go down again, with nuclei heavier than iron? [duplicate]

As the strong nuclear force is a short range force, and as it is way stronger than Coulomb force, Lumen Learning answered my question as follows: “for low-mass nuclei, the nuclear attraction dominates ...
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3 votes
2 answers
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Can muons be used to reach the island of stability of superheavy elements?

While reading about the island of stability of superheavy elements[0], experimental approaches and related difficulties[1], an idea has formed in my head. Since I cannot find considerations of such ...
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-2 votes
1 answer
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Can we create new elements or make old elements using nuclear fusion and fission [closed]

Is it possible to use nuclear fusion and fission to create new elements? For example, if you have a carbon dioxide molecule, break the bond between carbon and oxygen, and use nuclear fusion/fission to ...
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2 votes
1 answer
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I thought specific activity was a property of the radionuclide?

How can specific activity of Mo-99 be higher for Mo-99 produced from fission than Mo-99 produced from neutron capture? I thought specific activity would be a property of Mo-99 so it will always be the ...
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4 votes
1 answer
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Why is hydrogen ion much more likely to be +1 than -1?

With the chem 101 description of the periodic table, we ascribe certain "desires" to elements. Atoms "want" a full valence shell; for alkali metals, that is most easily done by ...
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Should all radioactive elements with HL smaller than 1000 years have 90% of their atoms already decayed on Earth?

Should all radioactive elements with HL smaller than 1000 years have 90% of their atoms already decayed on Earth? If that kind of radioactive source is found today should almost all of its atoms be ...
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1 vote
2 answers
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Island of Stability in Astronomical Surveys

To the segment of nuclear physicists that predict that there is indeed an “Island of Stability” in super-heavy transuranic elements, where these atoms shouldn’t suffer the effects of radioactive ...
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Synthesis of new elements with Pb-126 as particle projectile?

Why isn’t Pb-126 used in the synthesis of new elements as a projectile against a target instead of Ca-48 considering it is heavier and has a double magic number of protons and neutrons, just like Ca-...
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4 votes
2 answers
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Can you expect to see Island of Stability nuclei in matter flung off of neutron stars?

Apparently, merging neutron stars fling off baryon-rich matter that condenses into heavy elements, and this has been observed electromagnetically. It's not clear to me from the above sources whether ...
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Why is helium-3 stable?

Why is helium-3 stable? Besides hydrogen, helium-3 is the only isotope that has a neutron-to-proton ratio less than 1. Why is it not radioactive?
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At what temperature are the most elements of the periodic table liquid? [closed]

For elements where 'liquid', is relatively easy to define, at which temperature are the most elements liquid, and which ones? Assume 1 atm
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Why does changing the number of protons cause such a fundamental change in an element? [duplicate]

When we change the number of electrons in an atom of an element, it constitutes an ion. When we change the number of neutrons of an element it constitutes an isotope. But when we change the number of ...
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3 votes
1 answer
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Why is aluminum more common in the solar system, etc. than sodium and fluorine?

I know that odd-numbered elements are less common than even-numbered ones, but why is aluminum more commonly created in the galaxy, apparently, than lighter odd-numbered elements? Sure, sodium and ...
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What are the origins of electronegativity?

Now, this might sound to be a chemistry oriented question. Today in physics class, we discussed bonds and electronegativity, and I wondered why it does originate. I would appreciate it if someone ...
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Strange behavior of Polonium -- can it be accounted for by heat and/or ionizing radiation?

I have read that Polonium does things like move against air currents or migrates within containers to (I think) different parts of the container. But I also read that a .5 gram chunk will reach 500 C. ...
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Which element is A?

Which element used to be represented by the letter A? I'm guessing sulfur but this is only a guess. It's mentioned in Gamow (1930), "Mass Defect Curve and Nuclear Constitution". Proceedings ...
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What are the major difficulties to the production of elements?

Searching online about this topic only gives results about nucleosynthesis (making elements by nature) and the 24 radioactive artificial elements. Why isn't there any information about methods to make ...
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