What happens to the half life of a radioactive substance as it decays?

Answer 1

the type of isotope

Answer 2

The istopes and that's it.

Answer 3

For a given isotope of a given element, the half-life is generally considered to be a constant. But there is more.

Different isotopes of different elements have unique half-lives. The half-life for a given element is based on the constituent isotopes in a sample: different isotopes of the same element can vary greatly in their half-lives.

It is the configuration of the nucleus which means it is either stable or unstable, giving rise to radioactive decay. Essentially it is the balance of the forces within the nucleus, between the protons and neutrons in it, that determines this. Thus you can have a stable nucleus of an element but adding another neutron upsets this and produces instability.

There are so many different radioisotopes it would take an encyclopedia to describe them all. What can definitely be said is that once a radioisotope is formed, its activity will follow the half-life curve regardless of external conditions such as temperature. The only way to change it is to irradiate it again in a reactor (neutron flux) to access the nucleus itself.

Answer 4

The half-life of any particular radioactive substance (isotope) is constant. It does not change as it decays. However, when decay does occur, there is a tendency to form other radioactive isotopes, what we call daughter products, and those can and do have their own half-lives. This, of course, complicates the measure of half-life, and forces analysis of energy levels and other chemical properties, i.e. not just count rate, in order to assess activity and its related half-life.

Answer 5

"Time required to reach the initial concentration oe a reactant to it half value is called half life period."
What are "the following"? However half life is a property of a particular isotope and can't be changed for that one, so the only way to change it is to convert it to a different isotope by neutron irradiation.
the type of isotope

Answer 6

In general, and at temperatures one might commonly find on Earth, temperature has

no appreciable effect on half life. If the temperature of an atom is elevated sufficiently,

we can get effects in which the question of half life becomes moot, because the atom is

no longer able to hold together in atomic form, but I am supposing that is not what this

question is about. There are certain circumstances, under which the half life might be

affected by temperatures that a person might consider more ordinary. One such place is

in a neutron rich environment, such as in the core of a nuclear reactor. Neutrons colliding

with the nuclei of atoms can cause the atom to become a different isotope of the same

element, to decay, or to undergo fission. The probability of the neutron colliding with the

nucleus depends on what is called the "nuclear cross section" which is measured in a unit

called a "barn." The nuclear cross section generally increases with temperature, though as

the temperature increases, the actual value goes up and down, depending on the

temperature and the specific isotope involved. So, in a neutron rich environment,

increasing the temperature generally reduces the half life.

All very interesting, I'm sure. Now, let me attempt an answer to the question:

For a large enough sample with enough atoms in it, the half-life doesn't change

as time passes and the atoms in the sample decay. If the half-life depended on

how much of the original sample remains, then there wouldn't be any such thing

as the 'half life' of a radioactive substance at all. It would have to be "the half-life

of this substance after 30 percent of it has already decayed" or some such number.

But you never see that. You only see "the half-life of this substance", and it doesn't

matter how much of it you start with, or how much of the original sample has already

decayed.

Answer 7

For a nucleus stationary by your side, nothing whatsoever. However, if the nucleus is passing you near the speed of light, relativistic effects will make the halflife seem to increase.

Answer 8

Under normal circumstances, nothing can affect the half-life.

Answer 9

anything but the isotope