Radioactive decay follows first-order kinetics. If a sample of I-131 decays from 25.0 mg to 8.25 mg in 12.8 days, what is the rate constant, k?

k = 0.0866 days⁻¹

Explanation:

The isotope decay of the atom follows the equation:

ln [A] = -kt + Ln[A]₀

Where [A] is the amount of the isotope after time t = 8.25mg

Time = 12.8days

k is rate constant

[A]₀ is actual amount of the isotope = 25.0mg

Replacing:

ln 8.25mg = -k*12.8days + ln 25.0mg

2.11 - 3.22 = -k*12.8days

-1.11 = -k12.8days

k = 0.0866 days⁻¹

the answer is a for sure mark brainliest i had got this right on usatestprep

the seeing the electronic configuration we can say that the element is fluorine.

fluorine is the most electronegative element in the periodic table.

but by only seeing the configuration we cannot say about its reactivity because we don't know if its configuration after excitation or by addition of electrons.

but if not then, it is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. as the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine.