# Question about the quotient of the charge and mass of an electron

Gold Member
TL;DR Summary
The quotient charge-mass of the electron is 1000 times greater than the one of the ion of hydrogen
hello
Witch of these are certain sentences?
a-$$\dfrac{e}{m_e}>\dfrac{H^{-}}{m_{H^{-}}}\cdot{1000}$$
b-$$\dfrac{e}{m_e}>\dfrac{H^{+}}{m_{H^{+}}}\cdot{1000}$$
The first accurate measurement of $$e/m$$ was made by english physicist J.J. Thomson in 1897, who demostrated that the quotient charge-mass of the electron is 1000 times greater than the one of the ion of hydrogen.
But it was cation or anion?;
This implied that electrons represent a very small portion of the mass of an atom.
Thanks!

Mentor
To be honest I am not sure what your question is.

If the mass difference between electron and hydrogen atom is large enough, it doesn't matter whether you work with cation or anion (try to calculate it).

However, I believe Thomson's experiment was designed around Crookes tube, which allowed comparing cathode rays with anode rays, so the opposite charges were implied.

Gold Member
Hello, Borek, I knew nothing except the quote I mentioned in my first post. I had to start asking something as fuzzy as you see. I am attending a course to access university for those aged more than 45. Afterwards I've done this: the elementary charge $$e$$ is the modulus of the charge of the electron and the proton, which is $$1,602\times{10^{-19}}\;C$$; $$m_{proton}=1,673\times{10^{-27}}\;kg$$; $$m_{electron}=9,109\times{10^{-31}}\;kg$$
I've equated proton to hydrogen ion, and I've called it $$H^+$$, and I've arranged this:
$$\dfrac{e}{m_e}>\dfrac{H^{+}}{m_{H^{+}}}\cdot{1000}$$
And that's all