The half-life of cesium-134 is 2.06 years. If you start with 24 atoms of cesium-134 and wait 2.06 years, how many atoms of cesium-134 will you
have left?
A. 6 atoms
B. 24 atoms
C. 48 atoms
D. 12 atoms
help please

Number of atoms of Cesium-134 left = 12 atoms

The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.  

Usually radioactive elements have an unstable atomic nucleus.  

The main particles are emitted by radioactive elements so that they generally decay are alpha (α), beta (β) and gamma (γ) particles  

General formulas used in decay:  

t = duration of decay  

t 1/2 = half-life  

N₀ = the number of initial radioactive atoms  

Nt = the number of radioactive atoms left after decaying during T time  

No=24 atoms

t1/2=2.06 years

T=2.06 years = t1/2

Since the decay time is the same as the half-life time, the number of atoms of Cesium-134 will be halved from 24 to 12.

Or we can use the formula above

D

Explanation:

Addition of 0.05 M HCl, will react with all of the C2H3O2- from LiAc which will give 0.05 M more HAc. So there will be no Acetate ion left to make the solution buffer. Hence, the correct option for the this question is d, which is adding 0.050 moles of HCl.