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2
votes
1answer
69 views

Why do the elements Tc and Pm have such low abundances?

What specific nuclear and electronic properties make these two elements (Tc & Pm) almost disappear from solar and galactic abundance tables?
2
votes
0answers
33 views

Isn't it entropy (disorderliness) that every atom in the universe is not of iron Fe?

The concept of mass defect and binding energy Iron has most mass defect and the greatest binding energy. It has the most stable nuclei. Nuclei with higher atomic number than iron undergo fission ...
1
vote
0answers
30 views

Bare Critical Masses of $^{241}$Am, $^{242m}$Am, $^{238}$Pu and $^{242}$Pu

$^{238}$Pu has 144 neutrons, and it has 2.8$\times$10$^{3}$ g$^{-1}$.s$^{-1}$ spontaneous fission neutrons and bare critical mass in 10 kg. $^{242}$Pu has 148 neutrons, and it has 1.7$\times$10$^{3}$ ...
0
votes
0answers
42 views

Element creation in space

In my astronomy magazine I recently saw the periodic system revisited where the elememnts were color-coded according to their production site. For example, Hydrogen was created from the early Universe ...
0
votes
1answer
53 views

How many known nuclides are there?

What is the current estimate for the number of nuclides? This is a very basic question, but I'm finding it remarkably hard to get a reliable, up-to-date answer. A few books published in the last 2-3 ...
0
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0answers
33 views

Elements Of the periodic table [duplicate]

Why even-numbered elements, with their even proton numbers are more abundant than odd-numbered elements ?
95
votes
11answers
14k views

Why do fusion and fission both release energy?

I only have high school physics knowledge, but here is my understanding: Fusion: 2 atoms come together to form a new atom. This process releases the energy keeping them apart, and is very energetic. ...
51
votes
3answers
7k views

Why is hydrogen the most abundant element in the Universe?

Hydrogen is the most abundant element in nature. Does cosmological nucleosynthesis provide an explanation for why is this the case? Is the explanation quantitatively precise?
0
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1answer
71 views

When you see the atomic mass number for an element, does it take into account the atomic mass defect?

Sometimes I read that the official atomic mass number for an element on the periodic table only includes natural isotope ratios, other times I read that atomic mass defect, number of electrons, etc. ...
-1
votes
1answer
55 views

Are there processes other than fusion which can create very heavy elements? [closed]

Have there been hypothesized processes other than nuclear fusion which could possibly create heavy elements? For example these incredibly powerful particle accelerators we are continuously building ...
27
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3answers
13k views

If iron can’t undergo fusion, does that mean a black hole is mostly iron?

Since stellar fusion can’t progress beyond iron, and a large enough star collapsed into a black hole because an iron core stalled fusion, wouldn’t that mean all black holes are predominantly iron?
2
votes
1answer
208 views

Why is Helium 4 so stable?

I've been looking at stuff to do with binding energies and was wondering why Helium 4 is so stable. The fact everything up to carbon is less stable seems a bit odd. Is there a reason for this or ...
16
votes
2answers
2k views

Why do different elements have different number of isotopes?

For example: Carbon-12,Carbon-13 and Carbon-14 are three isotopes of the element carbon with mass numbers 12, 13 and 14 respectively. Lithium-6 and Lithium-7 for lithium,etc. My question is that are ...
5
votes
1answer
2k views

Why are there no stable isotopes with an atomic mass of 5 or 8?

One of the things I've encountered in my travels is the mass-5 roadblock. Rod Nave writes about it on his excellent educational hyperphysics website: The helium-4 nucleus or alpha particle with a ...
2
votes
3answers
136 views

Why plutonium and uranium are especially susceptible to do fission?

Why plutonium and uranium are especially susceptible to do fission? Are there any other elements that can also be subject to fission?
2
votes
1answer
289 views

Can we use a particle accelerator to create elements?

i'm a student of 11th grade. i studied about working of particle accelerators, cyclotrons in particular in a chapter of electromagnetism. i also read that the whole periodic table after element number ...
10
votes
2answers
471 views

Is this a correct demonstration for why elements above untriseptium cannot exist?

With the confirmation that elements 113, 115, 117, and 118 are indeed fundamental elements that are now to be named on the periodic table, the next question is: what is the highest atomic number ...
-2
votes
1answer
317 views

Characteristic Ka X-rays [closed]

In an experiment one observes the characteristic Ka X-rays of two elements at energies of 6.930 and 7.478 eV. The higher energy line is due to Ni. What element is responsible for the lower energy line?...
2
votes
2answers
690 views

How massive can an atom get?

After reading this thread, it appears to me that creating a new element is a game of chance some sort of an art. It also appeared to me that the higher you go, the harder it is to make an element. ...
1
vote
1answer
36 views

How to choose which elements to use when synthesizing an ultra-heavy element?

I've been told that synthetic ultra-heavy elements are produced by bombarding a light nucleus into a heavy one, and that several combinations are (at least in theory) possible, as long as the sum of ...
5
votes
1answer
2k 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
91 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 ...
2
votes
1answer
54 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 ...
4
votes
4answers
176 views

Why don't we have more elements?

By looking at the number of subatomic particles there seem to exist, there should be thousands of element configuration combinations possible. But we have found just over hundred elements to exist. ...
4
votes
1answer
105 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 ...
-1
votes
4answers
5k 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.: $\begin{array}{ccccr}...
1
vote
1answer
120 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 ...
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?
-5
votes
1answer
100 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
364 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 ...
8
votes
3answers
3k 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
458 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 ...
1
vote
3answers
959 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 ...
14
votes
1answer
615 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 ...
10
votes
1answer
12k 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 ...