1. Coulomb’s Law

2. Learning Target
I CAN qualitatively describe the relationship between charged particles using Coulomb’s Law

3. Criteria for Success
I CAN explain what happens to the energy of attraction and repulsion between charged particles as the magnitude of the charged particles increases or decreases
I CAN explain what happens to the energy of attraction or repulsion between charged particles as the distance between those charged particles increases or decreases

4. Coulomb’s Law Coulomb’s attraction repulsion
___________ Law is a fundamental understanding in chemistry that you will need to apply throughout this unit and future units that explains electrostatic ___________and _________, and is often referred to as the “inverse square” law.
𝐹=𝑘 𝑄 1 𝑄 2 𝑟 2
Coulomb’s
attraction
repulsion

5. Coulomb’s Law
It applies to charged particles, magnets, gravitation, etc. However, we are not interested in forces; we are interested in ________ of attraction or repulsion between particles (such as atomic structure, ionization energy, lattice energy, etc.)
So we perform a little calculus and we get :
𝐸=𝑘 𝑄 1 𝑄 2 𝑟
energy

6. Coulomb’s Law
And since we are not calculating, just comparing, let’s simplify to:
𝑬 ∝ 𝑸 𝟏 𝑸 𝟐 𝒓
E = energy of attraction or repulsion between charged particles
Q1 = charge of first particle
Q2 = charge of second particle
r = distance between charged particles

7. Attractive energy is negative Repulsive energy is positive
Coulomb’s Law
𝑬 ∝ 𝑸 𝟏 𝑸 𝟐 𝒓
𝑬 ∝ (+)(−) (+) + -
Attractive energy is negative
1 m + +
𝑬 ∝ (+)(+) (+)
Repulsive energy is positive
1 m

8. Coulomb’s Law
2. WHEN JUSTIFYING ANSWERS ON THE FREE RESPONSE USING COULOMB’S LAW:
a. The larger the _________, the larger the energy of attraction (if opposite charges) or the energy of repulsion (if like charges)
charge

9. - Coulomb’s Law 𝑬 ∝ 𝑸 𝟏 𝑸 𝟐 𝒓 + + + -
𝑬 ∝ 𝑸 𝟏 𝑸 𝟐 𝒓
+ + -
Greater charge = greater energy of attraction
1 m + -
Smaller charge = smaller energy of attraction
1 m

10. Coulomb’s Law distance
2. WHEN JUSTIFYING ANSWERS ON THE FREE RESPONSE USING COULOMB’S LAW:
b. The smaller the ___________ between the particles, the larger the energy of attraction (if opposite charges) or the energy of repulsion (if like charges)
distance

11. - Coulomb’s Law 𝑬 ∝ 𝑸 𝟏 𝑸 𝟐 𝒓 + + -
𝑬 ∝ 𝑸 𝟏 𝑸 𝟐 𝒓 + -
Greater distance = smaller energy of attraction
1 m + -
Smaller distance = greater energy of attraction
0.5 m

12. Coulomb’s Law
GUIDED PRACTICE