You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physics. You purify a sample of 2 grams. One of your colleagues steals half of it, and six days later you find that 0.2 gram of the radioactive material is still left. What is the half-life

2.58 days

Explanation:

Expression for rate law for first order kinetics is given by:

where,

k = rate constant  = ?

t = age of sample  = 6 days

a = initial amount of the reactant  =  1 g

a - x = amount left after decay process   = 0.2 g

a) to find the rate constant

b) for completion of half life:  

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

The half life is 2.58 days

the answer is 0.42 is that is an option. this question provides no info