Electron near nucleus

Winzer

1. The problem statement, all variables and given/known data
1) What is the magnitude of the electric field at a distance of 3.30 ×10−10 m from a thorium nucleus?
2)What is the magnitude of the force on an electron at that distance?
3)Treating the electron classically, that is, as a point object that can move around the nucleus at reasonably slow speeds, what is the period of the electron's motion?
Again treating the electron classically, how fast it it moving?

2. Relevant equations
[tex] E=\frac{Kq}{r^2}[/tex]
[tex] F=\frac{K q_{1} q_{2}}{r^2}[/tex]

3. The attempt at a solution
I can't find anywhere of what the charge of the thorium nucleus is.

rootX

not even in peridic table or google?

rootX

it's here:
http://www.webelements.com/webelemen...xt/Th/key.html

mgb_phys

Remember the electron and proton have the same charge, so you just need to know the number of protons in the nucleas = it's atomic number.

Winzer

not in Columbs,no

rootX

ohh.. you need to convert it on your own. You wouldn't get it from anywhere.
1 C =6.241506×10E18 electrons or protons

Winzer

so I got 1.4418e-17 C

rootX

yep, I also got the same thing