How do you figure out the coulombic attraction..?

Question

Like,
for ex: MgO LiCl

Answer 1

Coulombic attractive energy is based on opposite charges attracting.

Coulombic Energy= k*q1*q2/r
k is a constant 8.99*10^9 N*m^2/C^2
q1 and q2 are the charges on the ions. for example, in MgO its +2(1.6x10^-19)C and -2(1.6x10^-19)C. 1.6x10^-19C is a unit called elementary charge, its the charge on a single proton or electron. All charges are multiples of this, since we can't break charged particles into smaller things than that.

r is the distance between the ion centers. look up the ionic radius of Mg2+ and O2- online or in a text book. My chem textbook says .065*10^-9m and .140*10^-9m. Add those to get r.

Plug into the formula:
E=(8.99x10^9)(3.2x10-19)(-3.2X10^-19)/(.205x10^-9)=4.49x10^-18J

If you wanted the coulombic FORCE instead or also, you'd use:
F= k*q1*q2/r^2

The ionic radii for Li+ and Cl- are .060x10^-9m and .181x10^-9m. The charges are +qe and -qe, where qe=elementary charge=1.6x10^-19C

Answer 2

No, if I'm paying for it I'd rather slap a human. Do you have a stand-in instead of a lifesize figure? Lets go get Screech, he needs work anyway.