Mass number is the sum of protons and neutrons.
Atomic number is the total number of protons present.
Mass number = protons + neutrons
Atomic number = protons present.
From the above equations we can conclude that,
Atomic number= Mass number- neutrons.
Thus we can find out the atomic number by subtracting the number of neutrons from the mass number.
<u>Answer:</u> The original element is ![_{84}^{212}\textrm{Po}](https://tex.z-dn.net/?f=_%7B84%7D%5E%7B212%7D%5Ctextrm%7BPo%7D)
<u>Explanation:</u>
Alpha decay is defined as the process in which alpha particle is emitted. In this process, a heavier nuclei decays into a lighter nuclei. The alpha particle released carries a charge of +2 units.
The released alpha particle is also known as helium nucleus.
![_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha](https://tex.z-dn.net/?f=_Z%5EA%5Ctextrm%7BX%7D%5Crightarrow%20_%7BZ-2%7D%5E%7BA-4%7D%5Ctextrm%7BY%7D%2B_2%5E4%5Calpha)
For the given alpha decay process of an isotope:
![^{Z}_{A}\textrm{X}\rightarrow ^{208}_{82}\textrm{Pb}+_2^4\alpha](https://tex.z-dn.net/?f=%5E%7BZ%7D_%7BA%7D%5Ctextrm%7BX%7D%5Crightarrow%20%5E%7B208%7D_%7B82%7D%5Ctextrm%7BPb%7D%2B_2%5E4%5Calpha)
<u>To calculate A:</u>
Total mass on reactant side = total mass on product side
A = 208 + 4
A = 212
<u>To calculate Z:</u>
Total atomic number on reactant side = total atomic number on product side
Z = 82 + 2
Z = 84
The isotopic symbol of unknown element is ![_{84}^{212}\textrm{Po}](https://tex.z-dn.net/?f=_%7B84%7D%5E%7B212%7D%5Ctextrm%7BPo%7D)
Hence, the original element is ![_{84}^{212}\textrm{Po}](https://tex.z-dn.net/?f=_%7B84%7D%5E%7B212%7D%5Ctextrm%7BPo%7D)
Answer:
pH = 2.25
Explanation:
pH is a measurement in chemistry defined as the -log [H₃O⁺]. Molarity [], is defined as the ratio between moles of solute (HCl) and the liters of solution
To solve this question we must find the molarity of the H₃O⁺ knowing: [HCl] = [H₃O⁺]
[HCl]:
0.0084moles / 1.500L
= 0.0056M = [HCl] = [H₃O⁺]
pH = -log [H₃O⁺] = -log [0.0056M]
<h3>pH = 2.25</h3>
The best and most correct answer among the choices provided by your question is the second option or letter B. Hydropower makes use of an <span>odorless, colorless, and tasteless resource is considered cleaner than other fossil fuels.</span>
I hope my answer has come to your help. Thank you for posting your question here in Brainly.
Answer:
0.50045
Explanation:
Because you have to look at a conversion table and move the decimal three places to the left. Hope this helps!