## What is the longest half-life of radioactive elements?

Physicists in France have measured the longest ever radioactive half-life – over twenty billion billion years – in a naturally occurring element that decays by emitting alpha-particles.

## What is half-life of radioactive element?

The half-life of a radioactive element is the time needed for half of the material to decay. The blue and orange points represent the original number of radioactive nuclei and those that decay; the number of blue points decreases by half at each step in time.

**What does it mean if an element has a long half-life?**

Half-life (symbol t1⁄2) is the time required for a quantity to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive.

**What is the definition of the half-life of a radioactive isotope?**

The time required for half the atoms of a particular radioisotope to decay into another isotope. A specific half-life is a characteristic property of each radioisotope. Measured half-lives range from millionths of a second to billions of years, depending on the stability of the nucleus.

### What element lasts longest?

The data helped the collaboration make the first definitive measurement of xenon-124’s half-life: 18 billion trillion years. “This is the longest lifetime that we have ever directly measured.”

### What is the average life of a radioactive element?

7.2 min

[SOLVED] The average life of a radioactive element is 7.2 min.

**How can you tell if an element is radioactive?**

A substance is said to be radioactive if it contains unstable nuclei and is able to naturally release energy in the process of shedding high speed charged particles, in an attempt to reach a stable state. With this, a non-radioactive substance will remain intact indefinitely unless acted upon by an external force.

**How long will it take uranium 238 to reduce by 50%?**

Uranium-238 has a half life of 4.51 billion years. This means that it would take billions of years for uranium-238 to decay into a ratio of half uranium-238 and half thorium-234.

## What is the shortest half-life of an element?

Hydrogen-7 ( about 23x10E-24) has the shortest half life.

## Why is half-life important?

Knowing about half-lives is important because it enables you to determine when a sample of radioactive material is safe to handle. The rule is that a sample is safe when its radioactivity has dropped below detection limits. And that occurs at 10 half-lives.

**How many half-lives until a drug is out of your system?**

Even further, 94 to 97% of a drug will have been eliminated after 4 to 5 half-lives. Thus, it follows that after 4 to 5 half-lives, the plasma concentrations of a given drug will be below a clinically relevant concentration and thus will be considered eliminated.

**How is the half life of an atom defined?**

Instead, the half-life is defined in terms of probability: “Half-life is the time required for exactly half of the entities to decay on average”. In other words, the probability of a radioactive atom decaying within its half-life is 50%.

### How is the half life of a radioactive isotope defined?

One of the most useful terms for estimating how quickly a nuclide will decay is the radioactive half-life (t1/2). The half-life is defined as the amount of time it takes for a given isotope to lose half of its radioactivity.

### Which is an example of a half life?

A half-life usually describes the decay of discrete entities, such as radioactive atoms. In that case, it does not work to use the definition that states “half-life is the time required for exactly half of the entities to decay”.

**What is the half life of a drug?**

In biology and pharmacology. A biological half-life or elimination half-life is the time it takes for a substance (drug, radioactive nuclide, or other) to lose one-half of its pharmacologic, physiologic, or radiological activity.