Electron held up against force of gravity

[IbrahimZCL]

Homework Statement

an electron is held up against the force of gravity by the attraction of a fixed proton some distance above it. How far above the electron is the proton?

Homework Equations

F= ((K)(Q1)(Q2))/R^2

Qe = 1.6x10^-19

The Attempt at a Solution

Using the formula for Coulombs Law I used the K constant of 9x10^9 and Qe for Q1 and Q2. This is all divided by R^2 (I'm solving for R). The problem is I don't know if there is a gravitational constant for Force or what I'm missing. What's the next step?

 

[rl.bhat]

Write F = mg where m is the mass of the electron.