Question

What are the units of a half-life?

Answer 1

We know that Half- life of the reaction is the time required for the concentration of a reactant to decrease to one half of its initial value. This period of time is called the half-life of the reaction. The half- life of the reaction is denoted by ‘${t_{1/2}}$’.

Complete answer:
The half-life of the reaction is defined as the specific amount of time required for a reactant concentration to decrease by half when compared to its initial concentration. So, the half-life denotes the time period so its unit will be the time.
Therefore, the unit of half-life is time. The half-life is the length of time that it takes for half of an initial sample to undergo a change. The half-life represents the radioactive decay of the specific atomic weight of an element.
We know the formula for half-life which gives the remaining atoms after a time ‘$t$’ and it starts with $N(0)$ atoms in a sample.
The formula is as follows:
$N(t) = N(0){\left( {\dfrac{1}{2}} \right)^{\dfrac{t}{{{t_{1/2}}}}}}$
Here, ${t_{1/2}}$ denotes the half-life of the reaction. This is clear from the formula that it must be unit less. Therefore, the unit of half-life is time that can be in minutes, seconds and hours.

Note:
The concept of half-life is widely used in chemistry and in chemistry to predict the concentration of substance over time. It plays a vital role in the administration of drugs into the targets as it is used to discover how drug decreases in the target once it has been absorbed in a period of time.