Answer:
The presence of neutrons
Explanation:
Based on gold foil experiments, Rutherford proposed a atomic model known as Rutherford'd model or nuclear model or planetary model of the atom.
As per this model, most of the mass of the atom is concentrated in the center of the atom known as nucleus.
Electrons revolve around it same as planet revolve around sun.
Since, neutrons had not been discovered at the time of Rutherford'd model, therefore, as per the Rutherford'd model, nucleus is only made of protons.
Therefore, the correct option is option B
Answer:

Explanation:
Hello!
In this case, since pyridinium chloride has a pKb of 8.77 which is a Kb of 1.70x10⁻⁹ and therefore a Ka of 5.89x10⁻⁵ which means it tends to be acidic, we write its ionization via:

Because it is a Bronsted base which donates one hydrogen ion to the water to produce hydronium. Thus, we write the equilibrium expression with the aqueous species only:
![Ka=\frac{[C_5H_5NCl^-][H_3O^+]}{[C_5H_5NHCl]}](https://tex.z-dn.net/?f=Ka%3D%5Cfrac%7B%5BC_5H_5NCl%5E-%5D%5BH_3O%5E%2B%5D%7D%7B%5BC_5H_5NHCl%5D%7D)
In terms of the reaction extent
, we write:

Thus, solving for
we obtain:

Clearly the solution is 0.0048 M because to negative values are not allowed, therefore, since it equals the concentration of hydronium which defines the pH, we write:
![pH=-log([H_3O^+])=-log(0.0048)\\\\pH=2.3](https://tex.z-dn.net/?f=pH%3D-log%28%5BH_3O%5E%2B%5D%29%3D-log%280.0048%29%5C%5C%5C%5CpH%3D2.3)
Best regards!
the speed of arrow is 83m/per second
that means
83metres = 1 second
●The arrow would cover the distance of 83 metres in 1 second
may this helps you
bye
Even in pitchblende, polonium is exceedingly rare: 1,000 tons of ore must be treated to yield 40 milligrams of polonium. It has a one-part-in-ten-thousandth-thousandth-thousandth-thousandth-thousandth-thousandth It is found in nature as a byproduct of the radioactive decay of uranium, thorium, and actinium.
Atomic Number: 210