Why Are Heavy Elements Radioactive But Light Elements Aren't?

[Gizmo j]

I know that the sun is nuclear and is made of hydrogen and helium, which are the 2 lightest elements.

But on this periodic table I have, hydrogen and helium are not radioactive, but the heaviest elements are radioactive...

What gives?

 

[Torn Mind]

Tritium - Wikipedia

en.wikipedia.org

 

[shortylickens]

unstable and free electrons.

You go read up on physics you get a MUCH more thorough example.

 

[HomerJS]

I know that the sun is nuclear and is made of hydrogen and helium, which are the 2 lightest elements.

But on this periodic table I have, hydrogen and helium are not radioactive, but the heaviest elements are radioactive...

What gives?

Yeah it’s unstable elements that have radioactive decay. The unstable elements are more easily used for fission U or Pu

 

[biostud]

You need an isotope chart, that will show you that lighter elements have specific isotopes which are radioactive as well.

 

[sdifox]

Did you manage to miss science in high school?

 

[biostud]

I know that the sun is nuclear and is made of hydrogen and helium, which are the 2 lightest elements.

But on this periodic table I have, hydrogen and helium are not radioactive, but the heaviest elements are radioactive...

What gives?

Helium has radioactive isotopes:

Isotopes of helium - Wikipedia

en.m.wikipedia.org

 

[Brainonska511]

The sun is undergoing nuclear fusion, which is not necessarily radioactivity in the colloquial meaning. That process doesn't necessarily require radioactive isotopes. However, for its mass, it does require lighter elements to maintain that fusion process (if I recall, fusion in stars can create elements up to iron, depending on the star size. Heavier elements require supernovas).

After bismuth, the larger, heavier elements do not have stable isotopes and undergo radioactive decay, which eventually leads to stable isotopes. And as pointed out, there are radioactive isotopes for lighter elements as well - they are just generally more rare.

 

[biostud]

And as pointed out, there are radioactive isotopes for lighter elements as well - they are just generally more rare.

Because they are unstable and eventually decay info stable isotopes

 

[Brainonska511]

Because they are unstable and eventually decay info stable isotopes

Well, yes. The same issue plaguing radioactive heavy elements plagues radioactive light elements.

 

[Muse]

Partly it's because there are far fewer isotopes of any stability of light elements. Heavy elements can have many isotopes, some of which are radioactive.

 

[Muse]

The sun is undergoing nuclear fusion, which is not necessarily radioactivity in the colloquial meaning. That process doesn't necessarily require radioactive isotopes. However, for its mass, it does require lighter elements to maintain that fusion process (if I recall, fusion in stars can create elements up to iron, depending on the star size. Heavier elements require supernovas).

Yes, and a lot of what makes you possible was created in supernovas.

 

[BoomerD]

I

at people giving gizmo serious answers to his "hit and run" questions.

 

[Paperdoc]

Radioactivity is a property of individual isotopes of each element. And it results from the breakdown of the arrangement of particles in the NUCLEUS of the isotope, having nothing to do with the electrons surrounding that nucleus. An isotope is considered unstable if it does spontaneously break up part of that nuclear structure and emit a particle or energy wave.

An ELEMENT is defined specifically by the number of PROTONS in the nucleus. This is its ATOMIC NUMBER. The nucleus also contains a some NEUTRONS. The NUMBER of neutrons in a nucleus of the same Atomic Number is how the different ISOTOPES are defined. In general, having more Neutrons than Protons is less stable, and the greater the excess the less stable. A larger excess of neutrons is likely to mean a much less stable isotope that WILL break apart quickly and cease to exist. So for the LIGHT ELEMENTS and the probability of having several different isotopes with increasing neutron count that are stable enough to exist is much smaller than for heavy elements. Among the heavier ones, there are many with FEWER Neutrons than Protons, and that opportunity is very limited for the light elements with few protons to begin.

For each element there are found to be in nature a particular distribution of isotopes. LOTS of the most stable isotope, and small amounts of the less stable ones. In fact, that distribution is slightly different depending on where that sample its taken, which reflects how long that sample has existed since it was made and left there. What the Periodic Table shows as the ATOMIC MASS of each element is the AVERAGE mass of samples we have examined, taking into account the actual mass or each isotope and its relative abundance. So the values are never whole numbers, but always decimal fraction numbers.