# Electrostatic Force between the sodium ion and the chloride ion.

1. Sep 6, 2011

### Physics Help!

In solid sodium chloride (table salt), chloride ions have one more electron than they have protons, and sodium ions have one more proton than they have electrons. These ions are separated at about 0.28 nm. Calculate the electrostatic force between the sodium ion and the chloride ion.

What I did was the following:
F=k|q1*q2|/r^2

F=8.99e9(1.602e-19*1.602e-19)/(2.8e-10)^2
F= 2.94e-9 N

I try to submit it on Connect but it says is wrong. I tried with 2.94e-9 N and 2.9e-9 N. Can someone please tell me what I'm doing wrong.

2. Sep 6, 2011

### SammyS

Staff Emeritus
What is the direction of the force?