Hello!
The mass number in isotope notation is denoted A, the atomic number is denoted as Z, and the element is denoted as X.
In the given isotope, the mass of the isotope is 212 amu, and the atomic number is 82.
We know that the number of electrons, and protons are equal to the atomic number. Therefore, there are 82 protons. Also, to find the number of neutrons, we subtract the atomic number from the atomic mass.
212 - 82 = 130 neutrons
<u>Final answers</u>:
- Atomic Number: 82
- Mass number: 212
- Number of Protons: 82
- Number of Neutrons: 130
Chemical properties include reactivity with other elements of substances, toxicity, flammability, and chemical stability
just to name a few
B is the right answer "right"
Answer: It takes 3.120 seconds for the concentration of A to decrease from 0.860 M to 0.260 M.
Explanation:
Integrated rate law for second order kinetics is given by:
k = rate constant = 
= initial concentration = 0.860 M
a= concentration left after time t = 0.260 M

Thus it takes 3.120 seconds for the concentration of A to decrease from 0.860 M to 0.260 M.
Answer:
Explanation:
The reaction is given as:

The reaction quotient is:
![Q_C = \dfrac{[NH_3]^2}{[N_2][H_2]^3}](https://tex.z-dn.net/?f=Q_C%20%3D%20%5Cdfrac%7B%5BNH_3%5D%5E2%7D%7B%5BN_2%5D%5BH_2%5D%5E3%7D)
From the given information:
TO find each entity in the reaction quotient, we have:
![[NH_3] = \dfrac{6.42 \times 10^{-4}}{3.5}\\ \\ NH_3 = 1.834 \times 10^{-4}](https://tex.z-dn.net/?f=%5BNH_3%5D%20%3D%20%5Cdfrac%7B6.42%20%5Ctimes%2010%5E%7B-4%7D%7D%7B3.5%7D%5C%5C%20%5C%5C%20NH_3%20%3D%201.834%20%5Ctimes%2010%5E%7B-4%7D)
![[N_2] = \dfrac{0.024 }{3.5}](https://tex.z-dn.net/?f=%5BN_2%5D%20%3D%20%5Cdfrac%7B0.024%20%7D%7B3.5%7D)
![[N_2] = 0.006857](https://tex.z-dn.net/?f=%5BN_2%5D%20%3D%200.006857)
![[H_2] =\dfrac{3.21 \times 10^{-2}}{3.5}](https://tex.z-dn.net/?f=%5BH_2%5D%20%3D%5Cdfrac%7B3.21%20%5Ctimes%2010%5E%7B-2%7D%7D%7B3.5%7D)
![[H_2] = 9.17 \times 10^{-3}](https://tex.z-dn.net/?f=%5BH_2%5D%20%3D%209.17%20%5Ctimes%2010%5E%7B-3%7D)
∴

However; given that:

By relating
, we will realize that 
The reaction is said that it is not at equilibrium and for it to be at equilibrium, then the reaction needs to proceed in the forward direction.