# Atomic Structure: Half-life

## Atomic Structure: Half-life

# Understanding Half-life in Atomic Structure

## Basics of Half-life

**Half-life**refers to the time it takes for half of the radioactive atoms in a sample to decay.- It’s a measure of the rate at which a radioactive isotope decays and it’s expressed in units of time.

## Features of Half-life

- Each radioactive isotope has a unique half-life, which is always the same for that isotope.
- The half-life of a radioactive substance cannot be changed through physical means (e.g. temperature, pressure) or by chemical means.
- A longer half-life implies a slower decay rate and a shorter half-life means the isotope decays faster.

## Calculations Involving Half-life

- If given an amount or percentage of a radioactive isotope and its half-life duration, you can calculate how much of the isotope will remain after a given time period.
- Conversely, if given the starting and remaining amount of a radioactive isotope and the time elapsed, you can calculate the half-life.

## Applications of Half-life

- Knowledge of half-life is vital in many scientific fields such as dating archaeological samples (
**carbon dating**), medical imaging (**nuclear medicine**) and nuclear energy production. - It’s also useful in managing dangers associated with radioactive material, by predicting and controlling exposure.

# Key Learning Points

- A half-life is a time measurement and it expresses the decay rate of a radioactive isotope.
- The half-life of a radioactive substance is a fixed value and can’t be changed by external factors. Thus, knowing the half-life can predict how much of a radioactive sample will remain after a certain time.
- The concept of half-life is critical in areas such as archaeology, medicine, and nuclear power where it’s utilised to determine ages, diagnose conditions, and generate power, respectively.