B. because the other options are different sciences (biology and entomology)
Answer: Mercury-194 is an unstable isotope and hence is radioactive.
Explanation: Mercury-194 is an isotope of mercury, having formula 
Number of protons in this isotope = 80
Number of neutrons in this isotope = 114
This isotope is radioactive in nature and under decay process by Electron Capture.
Electron capture reactions are the reactions in which a proton in a nucleus absorbs an electron and convert it into neutron. The resulting nucleus will have a decreased atomic number and same atomic mass.
Reaction for electron capture of mercury-194 follows:
Answer:
250 mmol are left after 26.60 secs ≅ 26.6 seconds
Explanation:
zero order kinetics formula is:
[A] = [A₀] - kt
where [A] = amount left; [A₀] = amount remaining; k = rate constant; t = time
concentration [A₀] = mole/volume = 0.5 mole/2.0L = 0.25
[A] = 0.25 mole/2.0L = 0.125 M
k = 0.0047 Ms⁻¹
t = {[A]-[A₀]}/-k = (0.125 - 0.25)/(-0.0047) = 26.60 seconds = 26.6 seconds
the amount is reduced by half after 26.6 seconds
1. The subscript when writing the notation is always dedicated to the atomic number of the element. Since the atomic number for Mercury, Hg, is 80, then the subscript is <em>80</em>.
2. For the second problem, you just have to balance out the subscripts and superscripts of the reactions.
Superscripts: 203 = 203 + ?; To balance, the missing number would be 0.
Subscripts: 80 = 81 + ?; To balance, the missing number would be -1.
<em>Hence the particle produced is actually an <u>electron</u>, or a <u>beta particle</u> (not an element). The <u>mass number is 0</u>, and the <u>atomic number is 0 </u>(since it does not contain any proton).</em>
