Half life is the time that it takes for half of the original value of some amount of a radioactive element to decay.
We have the following equation representing the half-life decay:

A is the resulting amount after t time
Ao is the initial amount = 50 mg
t= Elapsed time
t half is the half-life of the substance = 14.3 days
We replace the know values into the equation to have an exponential decay function for a 50mg sample

That would be the answer for a)
To know the P-32 remaining after 84 days we have to replace this value in the equation:

So, after 84 days the P-32 remaining will be 0.85 mg
Answer:
Likely to gain electrons
Explanation:
The atom shown is likely to gain additional electrons to complete its electronic configuration.
- Since this is a neutral specie, the number of protons and electrons are the same.
- The atom has 16 electrons
- the number of valence electrons is 6
- If the atom gains two additional electrons, the octet configuration is attained
- Also, the atom can lose 6 electrons to become an octet
The atom will prefer to gain additional 2 electrons to give an octet configuration.