Why are high atomic number elements unstable?

The answer is that neutrons decay (via a weak interaction) into protons (and electrons) providing there is a spare quantum state for the proton to drop into. If this is not the case then the beta decay is “blocked” by the Pauli exclusion principle. Thus highly neutron rich nuclei will be unstable to beta decay.

What causes unstable atomic nuclei?

Instability of an atom’s nucleus may result from an excess of either neutrons or protons. A radioactive atom will attempt to reach stability by ejecting nucleons (protons or neutrons), as well as other particles, or by releasing energy in other forms.

At what atomic number do nuclei become unstable?

Note that all isotopes of elements with atomic numbers greater than 83 are unstable. The solid line is the line where n = Z. The nuclei that are to the left or to the right of the band of stability are unstable and exhibit radioactivity.

Why does an element become unstable?

Radiation is emitted from atoms when an unstable atom decays to become more stable. When an atom has extra neutrons or protons, it causes the element to become unstable.

Why are larger nuclei less stable than smaller nuclei?

Why is a larger nucleus generally less stable than a smaller nucleus? the strong force is short range, protons in a large nucleus are farther apart on average than in a small nucleus and the strong force is less effective between wide apart protons. a large nuclei contains a larger percentage of neutrons.

How does an element become unstable?

What happens when unstable nuclei gain stability?

Unstable systems gain stability by losing energy. Unstable nuclei lose energy by emitting radiation in a spontaneous process called radioactive decay.

Why are some elements unstable?

Why some elements are radioactive (unstable). When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable.

Why heavier nuclei are unstable?

In heavy nuclei, the Coulomb energy of proton repulsion becomes very significant and this makes the nuclei unstable. It turns out that it is energetically more profitable for a nucleus to throw out a stable system of four particles, i.e., an alpha particle, than individual nucleons.

What is the difference between a stable and unstable nucleus?

There are only certain combinations of neutrons and protons, which forms stable nuclei. If there are too many or too few neutrons for a given number of protons, the resulting nucleus is not stable and it undergoes radioactive decay. Unstable isotopes decay through various radioactive decay pathways.

Why do atoms have excess energy in the nucleus?

Because they have excess nuclear energy. This is due to disproportion in number of neutrons and protons, and the nucleus tends to establish balance in the number of these particles, and to fall to lower energy state. This happens by radioactive decay or nuclear fission.

Why are elements with high atomic number susceptible to nuclear fission?

So for elements of high atomic number, their nuclei can be very unstable and are susceptible to the process of nuclear fission. There are two types of nucleon in nucleus. One of them are neutral neutrons while other are charged protons. The charged protons repel with a long range unsaturated electrostatic force.

Why do large nucleons become unstable?

And the reason why large nucleons become unstable has to do with balance between the surface term and the repulsion term. Big nuclei have increasing Coulomb repulsion of protons. This can be only partly relaxed by neutron surplus because of the imbalance terms, so big nuclei still are more weakly bound.