1. Unit 4

2. Ionic compounds Negative particle in contact with positive particle: force of attraction between them. Particles with the same charge in contact: repulsive force between them. Both forces are electrostatic forces. Force of attraction (or repulsion) is given by Coulomb’s Law

4. Coulomb’s Law

6. Ionization Energy IE: energy needed to remove an electron from an atom Decreases down group (shielding), increases left to right in period (nuclear pull) Shielding creates a “core charge”, decreasing the overall force (coulombic attraction) pulling the valence electrons towards the nucleus So IE for valence electrons is lower.

10. PES: Photoelectron Spectroscopy

11. Also known as photoemission spectroscopy refers to energy measurement of electrons emitted from substances by the photoelectric effect, in order to determine the binding energies (ionization energies) of electrons in a substance.